PREHEAT oven to 350°F. Spray both sides of tortillas with cooking spray, then place in single layer on baking sheet. Bake 10 min. or until crisp and lightly browned.
MEANWHILE, cook rice in large saucepan as directed on package. Add beans, corn and taco seasoning mix; stir. Cook 5 min. or until heated through, stirring occasionally.
TOP tortillas evenly with the rice mixture, lettuce, salsa and cheese.
serving size = 2 tostadas