1. In a bowl, mix together tuna, corn, bell pepper and cheese.
2. Spread ¼ of the filling over half of each tortilla. Fold tortilla in half over the filling.
3. Heat each quesadilla in a skillet over medium heat until the cheese is melting.
4. Turn the quesadilla over and cook for an additional 30 seconds to 1 minute.
5. Refrigerate leftovers within 2 hours.