Arrange Taco Shells upright in baking dish (use crumbled up foil if needed to help shells stay upright.) and bake for 3 minutes.
Remove taco shells form oven and sprinkle thin layer of shredded cheese over bottom of shells. Return to oven for 5 minutes or until cheese is melted.
While the tacos shells are baking, heat oil in a nonstick skillet over medium-high heat. Add in the peppers and onions and saute for 2-3 minutes or until softened. Add in drained beans, taco seasoning, and ¼ cup of water. Saute for another 4-5 minutes or until sauce is thickened and beans are warm. Turn off the heat and mix in the zest of 1 lime. Taste and add in more salt if desired.
Scoop about ¼ cup beans onto each taco. Sprinkle with additional cheese and return to the oven for 5 minutes, or until cheese is melted.
Serve with desired toppings and avocado cream.
In a small food processor or blender, mix together avocados, salt, lime juice, and cilantro together until smooth. Or simply mash together with the a fork for a chunkier avocado mash.
In place of hard taco shells, feel free to use flour or corn tortillas. Simply heat your tortillas in a dry skillet for 20-30 seconds per side and fill with the bean mixture and top with cheese and desired toppings.
Skip the addition of sauteed peppers and onions if you have picky eaters.
Use the zest of one lime BEFORE slicing open to make the avocado mash. And be sure to only use the green skin of the lime, not the bitter white pith.
These tacos are best served immediately once assembled. The black bean mixture will keep in the fridge for up 3 days.
In place of homemade taco seasoning, use ¼ teaspoon salt, ¼ teaspoon paprika, ¼ teaspoon cumin, ⅛ teaspoon garlic powder, ⅛ teaspoon onion powder.