Prep the fish: Pat the fish very dry with paper towels. Cut into 1-inch-wide strips so they cook evenly.
Mix the spice rub: In a small bowl, combine chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, and pepper.
Season and coat: Toss the fish with the spice rub until well coated.
Sprinkle on the cornstarch and toss again to create a thin, even layer. Drizzle or spritz with a small amount of oil.
Preheat the air fryer: Set to 400°F (200°C) for 3–5 minutes. A hot basket helps the fish crisp.
Air fry the fish: Arrange the fish in a single layer in the basket.
Air fry for 6–9 minutes, flipping once halfway. The fish is done when it flakes easily and reaches 140–145°F (60–63°C). Avoid overcooking.
Make the slaw: While the fish cooks, mix cabbage, cilantro, lime juice, olive oil, and a pinch of salt.
Toss until lightly coated and crisp.
Stir the lime yogurt sauce: In a bowl, combine Greek yogurt, lime zest and juice, honey, grated garlic, and a pinch of salt. Adjust lime or sweetness to taste.
Warm the tortillas: Warm tortillas in a dry skillet, the air fryer for 1 minute at 350°F, or wrapped in a damp towel in the microwave for 20–30 seconds.
Assemble: Add slaw to each tortilla, top with 2–3 pieces of fish, and finish with a spoonful of lime yogurt sauce. Add any extras like avocado, pickled onions, jalapeños, or hot sauce.
Serve immediately: Squeeze fresh lime over the top and enjoy while warm and crisp.