Preheat oven to 450 degrees F. Coat a very large baking sheet with nonstick cooking spray; set aside. In a large nonstick skillet, heat oil over medium-high heat. Add sweet pepper, onion powder, and chili powder. Cook about 5 minutes or until pepper is tender, stirring occasionally. Stir in corn, beans, 1 cup of the cheese, and the salsa. Cook and stir until the mixture is heated through and cheese is melted.
To assemble the quesadillas, divide bean mixture among tortillas, spreading evenly over half of each tortilla. Fold over, pressing down gently. Place on prepared baking sheet. Sprinkle quesadillas with remaining 1/2 cup cheese and, if desired, olives.
Bake about 10 minutes or until cheese is melted and tortillas are golden brown and crisp. Cut each quesadilla into quarters. If desired, top quesadillas with sour cream.