Prepare chicken: Slice each chicken breast horizontally into thin, flat pieces (about 3–4 slices per breast). Pat dry with a paper towel to remove excess moisture.
Mix spices: Combine paprika, smoked paprika, garlic powder, onion powder, salt, and brown sugar in a small bowl. Sprinkle evenly over chicken pieces. Add avocado oil and toss to coat thoroughly.
Air fry chicken: Preheat the air fryer to 415°F (210°C). Arrange chicken slices in a single layer in the basket, leaving a small gap between pieces. Air fry for 10 minutes, flipping halfway. For larger pieces, cook up to 13 minutes. Ensure an internal temperature of 165°F (74°C).
Optional dipping sauce: In a small bowl, whisk together mayonnaise, gochujang, garlic, soy sauce, and rice vinegar. Season with salt and pepper to taste. Serve alongside the chicken.
Serve: Let chicken rest for 2 minutes, then slice if desired. Enjoy immediately, crisp and juicy, with the optional dipping sauce.