In a large skillet, brown the ground beef.
Place the diced sweet potato into a microwave safe bowl and cook for 2-3 minutes or until tender.
Add the sweet potato and black beans to the skillet and stir to heat and combine
Add taco seasoning to the water mixed with cornstarch, and mix into the skillet to create a sauce over on mixture.
Have the tortillas ready (if they were cold, warm in the microwave for 20 seconds so they are soft and won't crack. Room temperature works best; you do not want them warm, or they will stretch too much.
Mix the flour and water.
With a spoon, spread a tablespoon of the flour mixture around the outer edge of the tortilla
Place 1/3-1/2 cup filling into the center of each tortilla.
Press the edges of the tortilla together and pinch so they stick together well, go over the edges twice to be sure they are sealed.
Heat a skillet with a couple of tablespoons of oil over medium heat and brown both sides of each tortilla. You can fill the pan with as many as will fit. Cook in batches until they are all cooked.