Place the steak in a bowl or resealable plastic bag with the lime juice, orange juice, soy sauce, oil, and garlic. Toss to coat evenly, cover, and let marinate for at least 15 minutes or up to overnight.

Heat a cast-iron skillet over high heat until very hot. Add the steak, reserving the marinade for later. Sear undisturbed for 1-2 minutes per side to get a nice crust. Reduce heat to medium-high and continue cooking for 2-3 minutes per side, or until the steak reaches your preferred doneness (medium-rare is recommended, about 130–135°F / 55–57°C).

Pour the reserved marinade over the steak and cook for 1 more minute. Remove from the skillet, let rest for a few minutes, then cut into cubes.

Add the steak to the tortilla(s) and top with salsa, onion, and cilantro. Serve.

Meal Prep Tip: Store the steak separately from the tortillas and toppings in airtight containers in the fridge. Reheat the steak briefly in a skillet before assembling.