If you are using dry black beans, soak them in water for approximately 24 hours. The next afternoon, rinse beans, add fresh water and simmer in a small saucepan until beans are soft.
Chop sweet potatoes in small square pieces. I cooked them in a 2 quart sauce pan with just enough water to cover the bottom. Cover with a lid and cook until sweet potatoes are soft but still keep there form. I added small amounts of chili, garlic and smoked spanish style paprika, mix than add salt and black pepper to taste.
You also have the option of roasting the sweet potatoes vs cooking it stovetop. If you decide to go this route: set oven at 425, drizzle sweet potatoes with olive oil, sprinkle with salt, black pepper, garlic granules or powder, smoked paprika, and chili powder. Roast potatoes until they pierce easily with a fork.
Slice one large onion, add olive oil to a frying pan, place on low to medium heat, add onions and cook until caramelized. Stir onions frequently to make sure they don't burn or get to brown. Lower the heat if necessary.
Wrap the tortilla shells in aluminum foil and place in the oven at the lowest temperature possible. Keeping the tortilla shells warms helps to prevent them from breaking when folded.
I topped the sweet potatoes and black beans with caramelized onions, avocado, cilantro and red onions.
Drizzle with my homemade spinach jalapeño pesto or your favorite hot sauce.