Heat a large skillet over medium-high heat. Add the steak and cook for about 5 minutes per side until cooked through. Remove from the skillet and set aside.
Add the olive oil to the skillet and heat. Add the peppers and onions, stirring occasionally until softened, about 5 minutes.
Add the cumin, chili powder, salt and pepper and stir to combine.
Return the steak to the skillet and stir to combine everything.
Serve in warm tortillas with your favorite toppings.