In a small bowl, mix cumin, chili powder, onion powder, garlic powder, and salt. Season both sides of the steak.
Heat a 10-inch skillet over medium-high heat for 1 minute. Add ½ tablespoon olive oil and heat for 30 seconds. Cook the steak for 3 to 4 minutes per side, or until done to your liking.
Transfer the steak to a plate and cover loosely with foil. Let it rest while you cook the vegetables.
Add the remaining ½ tablespoon olive oil to the skillet. Add onions and bell peppers and cook, stirring often, for 5 minutes. Stir in the garlic and cook for 30 seconds more.
Slice the steak thinly against the grain. Return it to the skillet, add Worcestershire sauce, and stir for 1 minute to heat through.
Spoon the steak and vegetables into warm tortillas. Add any desired toppings and serve.
Notes
Prep Ahead: Slice the peppers and onions in advance and store in the fridge to save time at mealtime.
Bring Steak to Room Temp: If time allows, let the steak sit out for 20–30 minutes before cooking. It helps the meat cook evenly.
Slice Against the Grain: Cut the steak thinly across the muscle fibers for a more tender bite.
Add Lime at the End: A quick squeeze of fresh lime brightens the flavor just before serving.
Use a Cast Iron Skillet (or Any Heavy Skillet): A cast iron skillet helps get a great sear, but any heavy-bottomed skillet will work just fine.