Season the steak: In a small bowl, mix chili powder, cumin, paprika, garlic powder, salt, and pepper. Rub the mixture onto both sides of the flank steak.
Cook the steak: Heat avocado oil in a skillet over medium-high heat. Sear the steak for about 4–5 minutes per side (or until desired doneness). Remove and let it rest 5 minutes before slicing thinly against the grain.
Sauté the veggies: In the same skillet, add a splash more avocado oil if needed. Sauté bell peppers for 3–4 minutes until slightly softened. Add cherry tomatoes and cook another 2 minutes. Stir in black beans and heat through.
Assemble tacos: Warm tortillas or hard shells. Fill each with sliced steak, veggie-bean mixture, and your favorite toppings.
