Bring salted water to a boil in a 6 quart pot, add pasta and cook for 7 minutes, drain, and set aside to cool.
Sprinkle chicken breasts with salt and pepper and grill until done, allow to cool then slice thin on a diagonal and cut through once. Set aside.
Wash peppers, cut in half, cut out seeds and stem. Cut one half of each pepper into long thin strips; finely chop the second half of each pepper.
Whisk together dressing ingredients.
Combine pasta, chicken, peppers, onion and dressing. Mix until all ingredients are covered with dressing. Place in refrigerator for 1 hour before serving.