IF YOU think a cold noodle is a wet noodle, read no further. But if you, like I, love cold leftover spaghetti, read on.

If pasta is to be the food of the decade, then cold pasta salads are this summer's "in" variation on the theme.

If you doubt the cachet of pasta, read what Giuliano Bugialli, author and cooking teacher told Entree magazine: "Pasta will be very hot in the '80s. We're discovering that it's not really fattening if we eat it in the right proportion. Before there was the idea of pasta in a box and we knew only spaghetti and linguine. Now we're selecting different types of pasta for different sauces."

Hot sauces for hot pastas are more forgiving of canned and frozen ingredients. There is no such leeway in cold sauces for cold pasta salads.

Long simmering sauces which meld and mask flavors are not the stuff of which pasta salad sauces are made. Or if the ingredients are not absolutely fresh and barely cooked, it will be obvious.

Once considered not much more than a filler and budget stretcher by all but those in whose cultures noodles play an essential role -- Italians, Japanese and Chinese -- the various kinds of pastas now available show off their versatility in textures and tastes. Japanese buckwheat noodles, with more "tooth" and bite than Italian linguine, seem to be the perfect foil for the strong flowers of sauce made with dashi (fish broth), finger and soy sauce.

Chinese rice sticks becomes as crisp as potato chips when fried and are the perfect crunchy counterpoint to a salad of slivered chicken breast in a peanut butter sauce.

Then, of course, there is the homemade Italian pasta. While you wouldn't want to fry linguine to use in the chicken salad, or sauce it the way the buckwheat noodles are, it goes with almost everything else.

In preparing the recipes for this story I finally came to the conclusion that if it tasted good with cold potatoes or cold rice, it would probably taste good with cold linguine, or spaghetti. One of the great advantages of a fresh pasta salad over one made with potatoes or rice is that the pasta cooks so much more quickly, in about one minute. Even dried pasta cooks in about 12 minutes.

Pasta salads are versatile, serving as the first course before a substantial meal or as the main course for a lunch or simple dinner. Like other composed salads they travel well to picnics, and of course, offer the additional advantage of advance preparation.

If you are not yet making your own pasta, fresh pasta is available at several markets in the area. LINGUINE PRIMAVERA (4 to 6 servings as main course) 2 large stalks broccoli 2 small zucchini 4 asparagus spears 3 tablespoons fresh oregano 1 1/2 cups green beans, trimmed and cut in 1-inch lengths 3 tablespoons fresh thyme 1/2 cup fresh or frozen peas 6 tablespoons olive oil 2 cups thinly sliced mushrooms 1teaspoon finely chopped hot, fresh red or green chilies, seeds removed 1/4 cup finely chopped parsley 1teaspoon finely chopped garlic 3 cups red, ripe tomatoes, cut in 1-inch cubes 1/4 cup chopped fresh basil leaves 1 pound fresh linguine 2/3 cup freshly grated parmesan cheese 1/3 cup toasted pine nuts Salt and freshly ground black pepper 1/2 cup oil and vinegar dressing*

Trim the broccoli and break into bite-size flowerettes. Cut zucchinni into quarters. Cut each quarter into 1-inch lengths. Break off tough part of asparagus. Cut remaining spear into 3 equal parts. Steam each vegetable separately, until crisp tender. Steam the green beans with the oregano sprinkled over them. Steam the peas sprinkled with thyme. Drain immediately. Combine these five vegetables.

Heat 1 tablespoon oil in skillet and saute the mushrooms until they release their liquid. Add chilies and parsley to green vegetables. Heat 3 tablespoons oil in skillet; add half the garlic and the tomatoes. Cook about 5 minutes, stirring gently so that tomatoes don't break up. Stir in basil and set aside.

Add the remaining 2 tablespoons oil to a large skillet; stir in the remaining garlic and saute 1 minute.Add green vegetable mixture. Cook, stirring gently, just long enough to heat through.

Cook the linguine in boiling water until al dente. It cooks very quickly. Drain and run cold water over it to stop cooking. Mix the green vegetables with the linguine. Carefully mix in oil and vinegar dressing. (You may want to use a little more than 1/2 cup, but don't let the pasta swim in the dressing.) Place in serving dish with tomatoes in the center and chill if desired for several hours or serve immediately. To serve, sprinkle toasted pine nuts on top and pass the parmesan in a separate dish.

Make the oil and vinegar dressing with olive oil, basil vinegar and Dijon mustard. If you do not have basil vinegar, substitute white wine vinegar and fresh, chopped basil. -- Adapted from a recipe from Pasta Inc. SUMMER NOODLES (4 to 6 servings) 1 pound package somen (thin Japanese noodles) 1/4 cup sweet sake or dry sherry 1/4 cup Japanese soy sauce 1 cup dashi (see receipe under Cold Japanese Noodle Salad) 1 tablespoon finely chopped ginger 3 tablespoons thinly sliced green onions

Cook noodles in boiling water for 6 or 7 minutes, until quite soft. Drain and rinse with cold water to cool completely. Divide among six serving bowls. Heat the sake and ignite with match. Shake until flame dies out. Stir in soy sauce, dashi. Cool to room temperature. Serve in separate dipping bowls, into which each person dips the noodles before eating. Pass ginger and green onions for each person to mix with sauce. SEAFOOD PASTA SALAD (4 to 6 servings as main course) 1 pound fettucine 1/2 cup sliced pimiento-stuffed green olives 1/2 cup sliced ripe black olives 1/2 cup mayonnaise 1/2 cup plain yogurt 1 pound crabmeat or cooked lobster meat 1/4 cup olive oil 2 tablespoons white wine vinegar 1 clove garlic, minced 1 avocado, cubed

Cook the fettucine. Drain and run cold water over it to stop cooking. Combine olives with mayonnaise and yogurt. Fold in crabmeat or lobster. Whisk oil, vinegar and garlic. Mix avocado cubes with oil and vinegar. Combine olive-mayonnaise mixture with fettucine. Gently mix in oil and venegar dressing. Serve chilled. MANDARIN CHICKEN SALAD (4 servings as an appetizer) 2 cups peanut oil 2 ounces rice sticks or rice noodles 2 tablespoon peanut butter softened in 2 tablespoons water 1 1/2 teaspoons sugar 1 1/2 tablespoons white vinegar 1 tablespoon sesame oil 2 tablespoons imported soy sauce 1 tablespoon dry white wine 2 whole green onions, thinly sliced 2 slices red ginger, julienned* 1 boneless breast of chicken, poached in water until cooked, about 10 or 15 minutes Shredded lettuce Black sesame seeds* and chopped green onion for garnish

Heat peanut oil in deep pot. Add small amounts of rice noodles to hot fat and cook only until they puff up which is a matter of a few seconds. Remove noodles and drain, repeating process until all noodles are cooked.Drain thoroughly on paper towels. To drain properly, noodles should be cooked in a frying basket.

Leave noodles at room temperature. Combine the peanut butter mixture, sugar, vinegar, sesame oil, soy sauce and wine and mix to smooth paste. Add the green onions and ginger and mix well. Shread the chicken and add to the sauce. Set aside.

When ready to serve, cover four small plates with shredded lettuce. Mix the chicken and sauce quickly but gently with rice noodles and spoon on shredded lettuce. Sprinkle with a few black sesame seeds and a little green onion. Serve immediately.

Do not mix sauce and noodles until just before serving, but noodles can be fried ahead, the sauce prepared ahead.

*Available in Chinese grocery stores. COLD JAPANESE NOODLE SALAD (6 to 8 servings as appetizer) 1/2 cup vinegar 1 teaspoon sesame oil Light soy sauce Dashi broth (see recipe below) Sugar 6 to 8 large dried Japanese or Chinese mushrooms 2 eggs 1 tablespoon salad oil 1/2 pound Japanese buckwheat noodles (or Chinese wheat noodles) 1 large cucumber, peeled and cut in julienne strips 2 scallions, white and 1/3 of green part, finely sliced

Combine vinegar, sesame oil, 1/2 cup soy sauce 1/4 cup dashi broth and 2 tablespoons sugar in a saucepan. Simmer for 5 minutes and chill.

Soak the mushrooms in warm water for 15 minutes; squeeze out liquid with hands and discard the tough stems of the mushrooms. Cut the caps into thin strips. In a saucepan combine 1/4 cup dashi broth, 1 tablespoon soy sauce and 2 tablespoons sugar. Add the mushrooms and heat for 3 minutes; stir occasionally. Drain off liquid and reserve mushrooms in refrigerator.

Beat the eggs with 1 teaspoon sugar. Cook in skillet which has been grease with oil as you would for an omelette. Cool then cut omelette into julienne strips.

Cook noodles in plenty of boiling water until tender. Drain, rinse and chill.

All of these steps may be prepared in advance, as long as a day before. Mushrooms and sauce can be prepared two days ahead.

The final assembly must be done at the last minute.

Mix the noodles with the sauce.You may not want to use all the sauce, so taste the noodles before adding all the sauce. Heap the noodles on individual plates. Arrange the cucumber strips, mushrooms slices, egg strips on top in an artistic design. Sprinkle with scallions and serve. Dashi Broth (Japanese Soup Stock) (Makes 4 cups) 5 1/4 cups cold water 4-inch square dried kelp (kombu) 1/2 cup dried bonito (flaked katsuobushi)

Wash the kelp and cut in 1/2-inch wide strips. Combine the water, kelp and fonito flakes and bring just to boil. Remove kelp. Continue cooking, just below boil for 3 minutes longer. Stain to remove bonito flakes. The stock is now ready for use.

Substitutions: You can use beef stock, but it won't be the same. You can use cider vinegar instad of rice vinegar, vegetable oil instead of sesame oil, but all those changes will make a difference. You cannot use American soy sauce in place of imported Japanese soy sauce. Kikomen is acceptable.