Cut the corn tortillas into short, thin strips. Spray a baking sheet with a non-stick cooking spray and spread the corn tortilla strips in it. Spray the tortilla strips with the non-stick cooking spray and then sprinkle with salt to taste.

Bake in a 325-degree oven until lightly browned and crispy. Make sure to stir them around a couple times during baking. Remove from oven and set aside.

In a large bowl mix the diced sweet potatoes, oil, garlic powder, cumin, paprika and salt. Stir to mix well and then pour out onto a large baking sheet.

Bake in a 400-degree oven until sweet potatoes are tender and browned, about 25 minutes, stirring once. Remove from oven and set aside.

In a large skillet add the oil, onion, red pepper, garlic, cumin and salt. Sauté until onion is clear.

Add the black beans and continue to cook just until beans are hot. Remove from heat and gently fold in the roasted sweet potatoes.

Separate the lettuce leaves and lay them out. Scoop a spoonful of the vegetable mixture into each lettuce leaf. Then put a little bit of the diced avocado and tomato on top. Next sprinkle a little of the tortilla strips over the top. Serve warm or at room temperature.