Heat olive oil in a skillet over medium heat. Add onion and cook until softened, about 5 minutes.
Add garlic, chili powder, cumin, smoked paprika, and cayenne pepper (if using). Cook for 1 minute until fragrant.
Stir in the black beans and vegetable broth. Bring to a simmer and cook for 5-7 minutes, mashing some of the beans with a fork to create a thicker filling.
Season with salt and black pepper to taste.
Warm the corn tortillas according to package directions.
Fill each tortilla with the black bean mixture and add your favorite toppings.
Notes
For a spicier filling, add more cayenne pepper or a pinch of red pepper flakes.
You can add corn kernels or diced bell peppers to the black bean mixture for extra flavor and texture.
If you don’t have vegetable broth, you can use water.