Mix all marinade ingredients and add steak. Marinate 2–8 hours.
Remove steak and let sit 20–30 min. Pat dry lightly—don’t wipe off seasoning.
Preheat griddle to medium-high (450–500°F).
Add oil and lay down steak. Cook 3–4 min per side. Remove and rest.
Add a little more oil and cook peppers and onions 5 min in steak juices. Add a splash of water to deglaze.
Slice steak thinly against the grain.
Add steak back to griddle with veggies. Toss to combine.
Serve with warm tortillas or over rice.