WE ARE NOW nearing approximately the 66th salad of the summer, if you count the two weeks before Memorial Day. That's figuring two salads a day in preparation of unfurling a honed-down body on some sandy beach.

We offer one more plate of fodder-as-diet-aid. We borrowed this salad from Chez Maria, a Vietnamese restaurant in Georgetown frequented by the thin. Maria was amused that someone would call asking for the recipe for her Vietnamese salad. "It is so very simple," she said and giggled.

To test its interesting palatability we fed it to a dieter who tried a bathing suit on in the first week of May, meaning (this was a cavalier dieter) an average of 90 salads had passed through his tract, and he ate every delicious smidgen.

There is nothing fattening in the salad except the sugar, but that keeps you from wanting dessert.

The salad for dieters is a main course, for thin people an appetizer and feeds twice as many. CHEZ MARIA'S VIETNAMESE SALAD (4 main servings) 1/2 head of green cabbage, finely cut or grated into thin strips 1 carrot, grated 1 cubumber, halved lengthwise and seeded 1 bunch scallions, chopped 2 ribs celery, sliced thin across the rib 5 sprigs of fresh mint, leaves only 2 sprigs fresh coriander* or parsley 2 chicken breasts, boned Teriyaki sauce 1/4 cup lemon juice 2 tablespoons fish sauce* 3 teaspoons sugar 1 clove garlic, crushed

Place thinly sliced cabbage, carrot, cucumber, scallions, celery, mint and coriander in a large salad bowl.

Cut chicken breasts in small cubes and soak in teriyaki sauce for about 5 minutes. Saute or stir fry in a wok for about 5 minutes until cooked. Add to salad mixture.

In a separate bowl mix lemon juice, fish sauce (*available at Vietnamese markets on Wilson Blvd. in Arlington), sugar and crushed garlic. Stir until sugar is dissolved and remove garlic. Toss salad with dressing and let sit for 1/2 hour before serving.