Butterfly or thin the steak (optional): If your flank or skirt steak is thick, slice it horizontally to even out the thickness to about 1/2 inch. This helps it cook quickly and evenly in the air fryer.

Make the marinade: In a bowl, whisk orange juice, lime juice, soy sauce, olive oil, garlic, jalapeño, cumin, chili powder, smoked paprika, oregano, black pepper, salt, brown sugar or honey, and cilantro.

Marinate the beef: Place the steak in a zip-top bag or shallow dish and pour the marinade over it. Press out air, seal, and marinate in the fridge for at least 30 minutes and up to 8 hours. Don’t exceed 12 hours or the citrus can make the texture mushy.

Preheat the air fryer: Set your air fryer to 400°F (200°C) for 3–5 minutes. A hot basket helps with searing and browning.

Pat dry for better char: Remove the steak from the marinade and pat it dry with paper towels. Lightly brush with oil. Reserve 2 tablespoons of marinade to brush on after cooking (optional). Discard the rest.

Air fry the steak: Place the steak in a single layer in the basket. Cook at 400°F for 6–10 minutes, flipping halfway. Target 125–130°F for medium-rare or 135–140°F for medium. Time varies by thickness and air fryer model.

Rest and slice: Transfer to a cutting board and rest for 5 minutes. Slice thinly against the grain to keep it tender. If using skirt steak, cut into shorter sections first, then slice thin.

Warm tortillas: While the meat rests, warm tortillas in a dry skillet, over a flame, or in the air fryer for 1–2 minutes. Keep them wrapped in a towel so they stay soft.

Finish and assemble: Toss the sliced beef with any resting juices and brush with the reserved marinade if you like a glossy finish. Taste and add a pinch of salt. Load into tortillas and top with onion, cilantro, and a squeeze of lime. Add salsa or guac as desired.