Wrap tortillas in foil. Place in 300 degree oven for 10-12 minutes or till heated through.
Meanwhile, spray a large skillet with Pam. Add onion and garlic, stir fry for 2 minutes. Add red or green pepper, stir-fry for 1-2 minutes more or until veggies are tender crisp. Remove from skillet. Add oil to skillet. Add chicken, stir-fry 3-5 minutes or till chicken is tender and no longer pink. Return veggies to skillet. Add salsa. Cook and stir till heated through.
To serve, divide chicken mixture evenly among tortillas. Top with shredded lettuce. Dollop with yogurt and sprinkle with green onion. Roll up tortillas and serve.