Place black beans in a 1 quart or larger container. Cover completely with water. Allow to soak for at least 4 hours until they have doubled in volume. Drain off the water when ready to cook.
Preheat oven to 400. Roast a sweet potato or two until very soft. Remove from the heat and remove the flesh from the skin of the potato. Mash this until smooth. You want about a cup of sweet potato.
Bring a cup of water to a boil and add a pinch of salt. Add in the quinoa and simmer until the grains become soft, but not blowing apart. Drain off extra water and set aside.
Heat a coating of oil in a pot over medium high heat. Saute the onion and garlic until translucent. Then add in the black beans and cumin. Stir until well coated. Cover with water, and add a little salt and pepper. Cook down until most of the liquid has been evaporated and the beans are soft. Drain excess liquid. Cool down the beans and give them a rough chop.
Fold the potatoes, beans, and quinoa together in a mixing bowl. Add in herbs, and season well. Form the mix into burgers.
Mix the three cheeses together.
Heat a coating of oil in a heavy saute pan or skillet over high heat. Carefully place the burgers in the pan and sear for a minute or two per side. You want a nice brown color. Top them with cheese and place under a broiler or use a torch. Place the burgers on buns and top with salsa and/or other toppings as desired.
