Place the rice and beans in a mixing bowl. Remove the tops from the peppers and discard the seeds. Blanche the whole peppers and tops in a pot of boiling water for 5 minutes. Remove and drain.
Heat the oil in a medium skillet and sauté the onion for 3 to 4 minutes. Add the sweet corn and sauté 1 to 2 minutes. Place onions and corn in the mixing bowl with the rice and mix thoroughly.
Preheat the oven to 400° F. Stuff each pepper with the rice mixture and place in a casserole dish. Place the tops on the peppers. Combine crushed tomatoes, water, and salt. Pour into the baking dish. Cover the dish and bake for 45 minutes to 1 hour or until the peppers are tender. Remove tops the last 15 minutes to brown. Spoon some of the tomato sauce over the peppers before serving.
Per serving - 172 calories, 3 g fat (16% calories from fat), 7 g protein, 31 g carbohydrate, 7 g fiber, 0 mg cholesterol, 685 mg sodium