Heat two separate skillets with a tablespoon of oil in each. In the first skillet add the peppers, onions, cumin, chili powder, garlic powder, salt and pepper.
Thinly slice the flank steak against the grain. This is cutting in the opposite direction of the muscle fibers.
Add the sliced steak into the second hot pan and sear it. Season with additional salt and pepper as it cooks.
Slightly char the vegetables on high heat and then cook them down on medium until tender.
Once the steak is cooked to preference add in the cooked vegetables and stir.
Serve over cauliflower rice or make into a fajita salad.