Mediterranean grilled chicken salad

2/3 lb (2 medium) potatoes
           -- cut into 3/4-inch cubes
      4 oz Mushrooms; halved
      4 oz Green beans; halved,
           -steamed until crisp-tender

--------------------------------VINAIGRETTE--------------------------------
    1/4 c  olive oil
      2 tb White wine vinegar
      1    garlic clove; minced
      2 ts Minced fresh tarragon; OR..
    3/4 ts Dried tarragon
      2 ts Dijon-style mustard
    1/4 ts Sugar
    1/4 ts Salt
    1/8 ts Pepper
      2    chicken breast halves
           -- (boned and skinned)
           -- (about 6 ounces each)
    1/4 c  Chopped red onion
           Halved cherry tomatoes
           -- for garnish
 
  In 1-quart saucepan over medium heat cook potatoes, covered, in 2
  inches boiling water until tender, about 15 minutes; drain.
  Meanwhile, make vinaigrette:  In bowl whisk together all vinaigrette
  ingredients.  Place potatoes, mushrooms and beans in separate piles
  in large shallow dish; drizzle with 1/3 cup of the vinaigrette to
  coat.  Cover; let stand 15 minutes.  Heat broiler.  Meanwhile, in
  bowl add chicken to the remaining vinaigrette; cover and let stand 15
  minutes.  Remove chicken from vinaigrette (discard vinaigrette);
  broil 4 to 5 inches from heat source about 8 minutes until juices run
  clear when chicken is pierced, turning once.  To serve, slice chicken
  breasts and arrange on 4 plates with potatoes, mushrooms and beans,
  dividing equally.  Sprinkle with onion and garnish with cherry
  tomatoes.
  
  Menu:  garlic Bread, Tangerines or Melon Wedges
  
  Nutritional Information Per Serving:  540 calories; 31 g fat; 70 mg
  cholesterol; 410 mg sodium; 36 g carbohydrate; 5 g fiber; 31 g
  protein.
  
  Source: The Potato Board