Preheat broiler. Spray 12-inch skillet with cooking spray; heat over high heat. Add beef strips; cook and stir 4 minutes or until browned. Remove from skillet; cover to keep warm.
Add pepper and onion to skillet. Cook over medium-high heat 3 to 4 minutes or until crisp-tender. Stir in undrained tomatoes. Cook until hot and most of liquid has evaporated.
Open up each roll; top evenly with beef. Divide vegetables evenly among rolls. Place open rolls on baking sheet; sprinkle cheese over vegetables. Broil 4 inches from heat 1 to 2 minutes or until cheese melts.