Servings: Serves 4
Preheat oven to 400°.
Place 2 tortillas in an ovenproof dish. Add corn, beans and rice to cover the tortillas and sprinkle with cheese.
Put tostada into the oven until the cheese melts and the beans bubble around the edges, about 7 to 8 minutes.
Take the dish out of the oven and top with chopped lettuce, tomato, salsa, chopped scallions and chopped cilantro. Sprinkle with lime zest if desired. Cut into 4 portions and serve immediately.