HEAT oven to 375ºF.
BROWN meat in large skillet; drain. Return meat to skillet. Add 1/2 cup beans, and 1/4 cup each salsa and cheese; mix well. Stir in onions.
PLACE 4 tortillas in single layer on baking sheet sprayed with cooking spray; top with meat mixture and remaining tortillas. Cover with salsa, spreading to edges of tortillas.
BAKE 15 to 20 min. or until heated through. Sprinkle with remaining cheese; bake 2 to 3 min. or until melted.
SERVE topped with sour cream and cilantro.