Preheat oven to 450 degrees. Place tortillas on baking sheet; coat both sides with cooking spray. bake 5 minutes or until lightly browned and crisp. Remove; set aside.
Coat large nonstick skillet with cooking spray. Add bell pepper, cook and stir 4 minutes. Add chicken, garlic, chili powder and cumin; cook and stir 4 minutes or until chicken is no longer pink in center. Add 1/4 cup salsa and green onions; cook and stir 1 minute. Remove skillet from heat; set aside.
Combine refried beans and remaining 1/4 cup salsa in a microwavable bowl. Cook uncovered at high 1 1/2 minutes or until beans are heated through.
Spread bean mixture evenly over tortillas. Spoon chicken mixture and tomato over bean mixture. Garnish with sour cream and add shredded lettuce if you desire.