In a medium saucepan, cook the quinoa in the 2 cups of liquid, as directed on the package. As it nears it's cooking time (after about 15 minutes), stir in the diced tomatoes undrained and the black beans. Add the ground cumin and the lime juice. Continue cooking for about 10 minutes, or until any remaining liquid cooks off. Season with salt and pepper to taste. Spoon into warm tortillas, roll and eat.
If you want a little zing in your burritos, use Rotel diced tomatoes with green chilies in place of the diced tomatoes.
In a mixing bowl, combine the avocado, tomato, green pepper and add some ground cumin, chopped cilantro, lime juice and salt and pepper to taste.
Option #1: Serve the "guac de gallo" on the side.
Option #2: Serve the "guac de gallo" inside the burritos.
Either way, there won't be anything left on your plate!