In a bowl, combine the reduced-fat shredded cheese, grated onion, drained corn, drained and rinsed black beans, and salsa.
Mix well.
Evenly spoon the cheese and vegetable mixture onto one half of each flour tortilla.
Fold over and gently press together.
Working in batches, place the filled tortillas in a lightly greased skillet over medium heat.
Cook until the quesadillas are golden on one side, then flip and cook until the other side is golden.
Slice the Cheesy Veggie Quesadillas into wedges to serve.