1. Combine rice and water in a saucepan, and bring to a boil. Reduce heat to low, cover, and simmer for 35 to 40 minutes, or until tender. Remove from heat, and cool.
2. Place black beans and pinto beans into a colander or strainer, and rinse. Add corn and diced tomatoes with green chilies, and toss to mix. Transfer to a large bowl, and mix in rice and cheese.
3. Divide the mixture evenly among the tortillas, and roll up. Wrap individually in plastic wrap, place into a large freezer bag, and freeze. Reheat as needed in the microwave for lunch or snacks.