Preheat oven to 400. Prepare a 13" x 9" pan with cooking spray; set aside. In a mixing bowl, combine hot dog slices, beans, ketchup, and mustard. Mix well. Pour into prepared pan. In a another mixing bowl, combine egg whites, milk, and cornmeal. Mix well. Spoon evenly over hot dog mixture. Bake for 35 minutes, or until light brown.