In a large skillet combine onion, green pepper, undrained tomatoes, picante sauce, garlic, and cumin. Bring to boiling; reduce heat. Simmer,uncovered, for 10 min. Stir in beans. In 1 13x9x2 baking dish spread 1/3 of the bean mixture over bottom. Top with half of the tortillas, overlapping as necessary, and 1/2 of cheese. Add another 1/3 of the bean mixture, then remaining tortillas and bean mixture. Cover and bake in 350 over for 30 min or till heated thoroughly. Sprinkle with remaining cheese. Let stand 10 min. If desired, top with tomato slices,lettuce green onion, and olives. Cut into squares to serve. If desired, serve with sour cream or yogurt. Makes 10-12 side dish servings or 6-8 main servings.