1Spray 12-inch nonstick skillet with cooking spray; heat over medium heat. Cook onion and bell pepper in skillet 6 to 8 minutes, stirring frequently, until tender. Remove vegetables from skillet; keep warm.
2Mix turkey, chili sauce and garlic powder. Shape mixture into 4 patties, each 5 inches in diameter. Cook patties in skillet over medium heat 4 to 5 minutes on each side or until turkey is no longer pink in center.
3Top each patty with about 1/4 cup of the vegetables; sprinkle with 2 tablespoons of the cheese. Cover and cook 1 to 2 minutes or until cheese is melted. Spread 1 teaspoon mayonnaise on each slice toast. Top each with patty.