Cook spinach according to directions, pressing out any excess water once fully cooked. Sprinkle spinach with garlic powder and salt and set aside. Sprinkle cumin, onion powder and garlic powder over black beans, stirring to evenly coat beans with spices and set aside. Sprinkle mashed sweet potato with cinnamon and stir to combine. Then combine sweet potato mixture, spinach mixture, grains and black beans in a large bowl, stirring to evenly incorporate, and scoop mixture into the center of the shell. Drizzle with hot sauce if desired.