Another "Black Bean Quesadillas" recipe ranks higher.
In a large skillet, add the oil and saute the onion and garlic until soft. Mix in beans, bell pepper, tomatoes, and corn. Cook until heated through.
Place a tortilla on a plate or flat surface, sprinkle some cheddar cheese over the tortilla. Spoon some of the bean and vegetable mixture over the cheese. Top w/ another tortilla. Heat tortilla until cheese is melted.