In a large skillet over medium heat, add a splash of oil and cook chopped onions for about 5-7 minutes until soft and golden. Stir in minced garlic, chipotle pepper in adobo, chili powder, and cumin; cook for 1-2 minutes until fragrant.

Add drained black beans and a splash of vegetable stock to the skillet, gently mashing some of the beans. Let the mixture simmer for about 10 minutes, stirring occasionally. Finish with a squeeze of lime juice.

Wrap corn tortillas in a damp paper towel and microwave for 30 seconds to steam, making them pliable.

Lightly coat a baking sheet with oil. Take a warm tortilla, spread the black bean mixture on one half and sprinkle with cheese. Fold and place on the baking sheet.

Preheat your oven to 400°F (200°C) and bake the tacos for 15-20 minutes, flipping halfway through until browned and crispy.

Remove from the oven and let cool for about 5 minutes. Serve with toppings like guacamole or salsa.