Season the steak. In a bowl, toss the sliced steak with cumin, chili powder, smoked paprika, oregano, salt, black pepper, and half the lime juice. Add 1 tablespoon olive oil and the minced garlic. Let it sit while you prep the vegetables—about 10 to 15 minutes.
Cook the peppers and onions. Heat the remaining 1 tablespoon olive oil in a large skillet over medium-high heat.
Add the onions and peppers with a pinch of salt. Cook, stirring occasionally, until softened and lightly charred in spots, 6 to 8 minutes. Transfer to a plate.
Sear the steak. In the same skillet over high heat, spread the steak in a single layer.
Don’t overcrowd—work in batches if needed. Sear 1 to 2 minutes per side until browned and just cooked through. Return all steak to the pan, add the remaining lime juice, and toss quickly.
Warm the tortillas. Heat tortillas in a dry skillet over medium heat for 20 to 30 seconds per side until pliable, or wrap in a damp paper towel and microwave for 20 to 30 seconds.
Assemble. Lay a tortilla flat.
Add a scoop of peppers and onions, a generous portion of steak, and any optional fillings like rice, beans, cheese, and a spoonful of salsa or guac. Don’t overfill.
Wrap. Fold the sides in, then roll from the bottom up, tucking as you go to seal. Repeat with remaining tortillas.
Optional finish. For a toasty exterior, sear the wrapped burritos seam-side down in a lightly oiled skillet over medium heat for 1 to 2 minutes per side.