In a large bowl, mash the drained black beans with a fork or potato masher until mostly smashed but still a little chunky.

Add the cooked quinoa, breadcrumbs, chopped onion, minced garlic, cumin, smoked paprika, salt, and pepper. Mix until the ingredients are evenly combined and taste to adjust seasoning.

Form the mixture into 3–4 patties, pressing firmly so they hold together. If the mixture is too wet, add a tablespoon of breadcrumbs; if too dry, add a splash of reserved bean liquid or a little olive oil.

Heat a skillet over medium heat and add enough olive oil to coat the bottom. When the oil shimmers, add the patties without overcrowding.

Cook for about 5–6 minutes per side, flipping gently, until deep golden brown and crisp on both sides. Reduce heat slightly if the exterior browns too fast before the center is warm.

Serve the patties on toasted burger buns with your preferred toppings.