Preheat oven to 350°F (180°C). Spray a 9-inch (2.5 L) springform pan with cooking spray.
In a nonstick saucepan sprayed with cooking spray, cook corn over medium heat, stirring often, for 8 minutes, or until slightly charred. Set aside. Add oil to pan and cook onions and garlic for 4 minutes, stirring occasionally. Stir in red and green peppers; cook for 3 minutes, stirring occasionally. Stir in tomato sauce, charred corn, basil, chili powder, and cumin; cover and cook, stirring occasionally, for 6 to 8 minutes, until slightly thickened. Remove from heat.
In a bowl, combine black beans and white kidney beans.Mash roughly and stir into vegetable mixture.
In a small bowl, combine mozzarella, Cheddar, and Parmesan cheeses.
Place a tortilla in prepared springform pan. Spread with one-quarter of the vegetable–bean sauce. Sprinkle with one-quarter of the cheese mixture. Repeat layers three times, leaving a little cheese for the topping. Top with final tortilla; sprinkle with remaining cheese. Cover pan tightly with foil.
Bake for 20 minutes, or until heated through and cheese has melted. Cut into 8 wedges with a sharp knife.