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.

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.

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.

Mix ingredients together in a bowl and serve.

If you want to prepare multiple servings in advance, you can shred the carrots and lettuce and slice the onion in advance and store them in the fridge in a ziploc bag or tupperware container so you just have to dice a little cucumber and tomato and add a little dressing the next time.