Crumble the tempeh into small pieces using your hands or a box grater for a ground-meat texture.
Heat a non-stick skillet over medium heat and add the water, red onion, and bell peppers.
Sauté the vegetables for 4-5 minutes until they are tender and the water has mostly evaporated.
Add the crumbled tempeh, black beans, chili powder, cumin, garlic powder, sea salt, and black pepper to the skillet.
Cook for 6-8 minutes, stirring frequently, until the tempeh is lightly browned and the spices are fragrant.
While the filling cooks, mash the avocado in a small bowl and stir in half of the lime juice.
Warm the corn tortillas in a separate dry pan over medium heat for 30 seconds per side until pliable.
Fill each tortilla with the tempeh and bean mixture, then top with the avocado mash, remaining lime juice, and fresh cilantro.