Chop and sauté bell pepper and onion in saucepan with olive oil.
When done, add tomatoes, beans, and corn. Only add half the can of chilies, well use the rest later. Season with chili powder and cayenne pepper to taste. Cook together until hot.
While that is cooking, prepare the rice. When the rice is almost done cooking, dump the rest of the green chilies in with it and season with pepper and salt, to taste.
Line a casserole dish with tostadas and spoon a layer of chili over them. Lay down another lay of tostadas and cover that layer with rice and the rest of the chili. Put on one last layer of tostadas.
At this point, you can either bake it (if you want crispy tostadas) or let it sit for a few minutes first so that the juices soften up the bottom two layers of tostada. I prefer the latter.
Enjoy!