Heat a skillet over medium heat.
Add sliced bell peppers and onions to the skillet.
Sauté for about 5 minutes until they start to soften.
Add zucchini and cherry tomatoes, cooking for another 3-4 minutes.
Stir in the black beans and cook until warmed through.
Season with lime juice, salt, and pepper to taste.
Warm the corn tortillas in a separate pan or microwave.
Assemble the tacos by placing the vegetable mixture into each tortilla.
Top with diced avocado and chopped cilantro.
Drizzle with sour cream or yogurt before serving.