Preheat oven to 375°.
Heat 1 teaspoon vegetable oil in a large saucepan coated with cooking spray over medium-high heat. Add onion and garlic, and saute 3 minutes. Add 1/2 cup corn, 1/4 cup chiles, salsa, and next 5 ingredients (salsa through tomatoes), and bring to a boil. Reduce heat, and simmer 15 minutes. Pour mixture into a 13 x 9-inch baking dish coated with cooking spray, and sprinkle with 1/2 cup cheese; set mixture aside.
Combine cornmeal, flour, sugar, and 1/4 teaspoon salt in a medium bowl. Combine 1/2 cup corn, 1/4 cup chiles, 1/2 cup cheese, buttermilk, 1/4 cup oil, and egg whites, and add to cornmeal mixture, stirring just until moist. Spread batter evenly over bean mixture. Bake casserole at 375° for 25 minutes or until corn bread is lightly browned.