Heads of cauliflower and pints of cherry tomatoes have long tortured the single cook. Either forced to eat such produce for four consecutive days (with progressive degrees of boredom) or eventually throw the leftovers out, the solo breadwinner, shopper and cleanup crew is often relegated to a rather limited selection of fresh fruits and vegetables.

It's time for single cooks to stop bragging about those candidates for Ripley's Believe or Not hiding in the back of the hydrator, and to look to the supermarket or local fast-food restaurant salad bar as a building block for side dishes, main courses and desserts. After all, who ever said you could get only salad at a salad bar? If you analyze it, isn't it really just a produce section in miniature -- perfect for miniature households?

Stir fries are a natural. So are pasta dishes, such as primavera. Use the salad bar for fillings for omelets, sandwiches or tacos. Isolate one item for a side dish -- saute' six cherry tomatoes and a clove of garlic in a little olive oil and sprinkle with basil; drizzle the chickpeas with some oil and vinegar. The possibilities are as endless as the condiments in the single cook's refrigerator.

Salad-bar buying will not only cut down on wastage, but the prewashed and precut items will save you time -- the commodity that single cooks (and family ones, too) spend hours saying they don't have.

Locally, supermarket salad bars are mushrooming. Giant now has salad bars in all of its 134 stores, and Safeway has salad bars in 96 of its stores. The number of items at these miniproduce markets is growing too, ranging anywhere from 30 to 60, with all sorts of new faces, like peas and purple cabbage.

Depending on the item, however, salad bars are often no bargain when compared to purchasing the same food in the regular produce section. The salad-bar items at both Giant and Safeway sell for $1.99 a pound; bean sprouts in the regular produce section at Safeway cost 69 cents per pound; at Giant, carrots are 39 cents per pound in the produce section.

But they may be more of a bargain for the single cook, who may end up throwing out money with unused produce purchased in the regular section. And remember that there are no inedible stems, rinds or leaves on the salad bar, which comes with the poundage of some produce in the regular section.

Although fast-food restaurant salad bars can be used for this new produce project, often they do not stock as many items as the supermarkets, will be more expensive since the tab is the same no matter how much you buy, and they do not have the compartmentalized (a la blue plate special) and smaller plastic containers that the supermarkets stock.

Also, it's difficult to tell whether the fast-food establishment is using sulfites on its salad bar, the additive that delays browning on salad bar ingredients, but which has been shown to cause allergic reactions in sensitive individuals. Both Safeway and Giant inform consumers with small placards at the salad-bar facilities that they do not use sulfites.

Retailers report that shoppers are already mixing and matching everything on salad bars, pairing fruits with vegetables in all kinds of combinations. Ann Brody, food coordinator of Giant's Someplace Special, which stocks a salad bar with more than 40 items ranging from homemade dressings for fruit and vegetable salads to hearts of palm and marinated mushrooms, frequently purchases dinner from the store's salad bar. Brody (who is not a single cook herself) makes these additional suggestions:

*For a quick vegetable soup, buy a can of good-quality chicken broth and add assorted fresh vegetables from the salad bar.

*Grab some mushrooms, peppers and onions from the salad bar and saute' them with some sausages for a sandwich. Or use the saute'ed vegetables for a burger topping.

*Use homemade dressings as bases for dips by adding extra fresh herbs and yogurt. Use the vinaigrette as a marinade, the blue cheese as a coating for skinless chicken breasts.

*Make a solo portion of strawberries romanoff with berries from the salad bar, a dollop of sour cream and a sprinkling of brown sugar.

Here are some other ideas to get the single cook to use the salad bar -- without buying a salad: SALAD BAR STIR-FRY (1 serving)

FOR THE FISH:

1/3 pound monkfish or other firm fillet, cubed

1/2 egg white

Cornstarch

Salt and pepper

FOR STIR-FRYING:

Vegetable oil

1 clove garlic, minced

1 1/2 teaspoons freshly grated ginger

FROM THE SALAD BAR:

1 cup mixed vegetables such as broccoli flowerets, baby corn, carrots, cauliflower, zucchini, bean sprouts or purple cabbage

FOR THE SAUCE:

1 1/2 teaspoons wine vinegar

1 teaspoon dry sherry

1/2 teaspoon sugar

1 1/2 teaspoons soy sauce

Dash of sesame oil

Combine cubed monkfish with egg white and lightly dust with cornstarch and salt and pepper.

Pour enough oil into wok or saucepan to coat bottom of pan. Heat until very hot. Add garlic and ginger and stir-fry for about 20 seconds. Stir-fry monkfish for about 1 1/2 minutes, until it turns white and begins to soften. Remove to a warm plate.

Adding additional oil if necessary, add vegetables to wok in order of their cooking time, stir-frying each for about 20 seconds. Carrots, broccoli, cabbage and cauliflower should go first, followed by peppers, zucchini and mushrooms, followed by scallions and bean sprouts.

Return monkfish to wok. Add combined sauce ingredients and stir-fry another 20 to 30 seconds, or until fish is fully cooked. Add sesame oil in last few seconds. Remove to a platter and serve with rice. TRIPLE MELON SOUP WITH MINT (1 serving)

2 ice cubes

2 teaspoons vegetable oil

1 tablespoon lemon juice

1/2 teaspoon dried mint or 1 teaspoon chopped fresh mint plus extra for garnish

1/2 cup plain yogurt

FROM THE SALAD BAR:

1 cup cantaloupe, honeydew and watermelon chunks, combined

1 tablespoon sunflower seeds

Place ingredients in blender or food processor. Blend until smooth. Garnish with fresh mint, if desired. EGG PIZZA (1 serving)

Vegetable oil

2 eggs

Salt and pepper

1/4 teaspoon oregano

1/4 to 1/3 cup tomato sauce

FROM THE SALAD BAR:

1/4 to 1/3 cup grated cheese

Pizza toppings such as zucchini, mushrooms, peppers, cauliflower or onions

Coat the bottom of a small skillet with oil and heat. Beat the eggs and add salt, pepper and oregano. Add to the skillet. Reduce heat. Allow the eggs to cook until the bottom is firm. Lift the edges, allowing uncooked mixture to run under. Cook until the top is nearly firm.

Spoon the tomato sauce over the eggs. Sprinkle with the cheese and top with zucchini, mushrooms, peppers, etc. Run under broiler until bubbly and cheese is melted. Adapted from "Italian Fast & Fresh," by Julie Dannenbaum (Harper & Row, $15.95). ANTIPASTO SANDWICH (1 serving)

1 baguette or pita bread round

2 slices salami or ham

2 slices provolone

FROM THE SALAD BAR:

Olives, onions, mushrooms, green bell or hot peppers, artichokes, tomatoes, Italian salad dressing

Split baguette or pita bread. Place meat and cheese on sandwich. Stuff with salad bar vegetables and drizzle with Italian dressing.