Sauté the aromatics. Warm the olive oil in a skillet over medium heat.
Add the onion and a pinch of salt. Cook 4–5 minutes until softened and lightly golden. Stir in the garlic and cook 30 seconds until fragrant.
Bloom the spices. Add cumin, chili powder, smoked paprika, and oregano.
Stir for 30 seconds to wake up the spices. This step adds big flavor.
Add beans and liquid. Stir in the black beans, tomato paste (if using), and 1/2 cup broth or water. Bring to a gentle simmer.
Cook 3–4 minutes to meld flavors.
Season and brighten. Add 1/2 teaspoon salt, several grinds of pepper, lime juice, and vinegar (if using). Taste and adjust: more salt for savoriness, more lime for brightness.
Blend to your preferred texture. Transfer to a food processor or use an immersion blender in the pan. Blend until creamy but not completely smooth, adding a drizzle of olive oil or a splash more broth as needed.
For chunkier texture, pulse a few times instead of fully puréeing.
Finish and serve. Taste again. Add a pinch more salt or a squeeze of lime if it needs a lift. Top with chopped cilantro if you like.
Spread onto warm tortillas and build your tacos with your favorite toppings.