Whisk the egg whites in a medium bowl and place the 1/2 cup cornstarch, salt, and pepper in a shallow dish.
Dip the chicken pieces into the egg whites, then dredge in the cornstarch mixture until each piece is fully and dryly coated.
Preheat an air fryer to 400°F (200°C) and lightly spray the basket with avocado oil.
Arrange the chicken in a single layer and cook for 12-15 minutes, shaking halfway through, until the internal temperature reaches 165°F and the exterior is golden-brown.
In a separate large skillet or saucepan, combine orange juice, zest, tamari, honey, vinegar, sesame oil, garlic, ginger, and red pepper flakes over medium heat.
Bring the sauce to a gentle simmer for 3-5 minutes, then whisk in the cornstarch slurry and stir until the sauce thickens to a syrupy consistency.
Add the cooked crispy chicken to the skillet and toss quickly to coat each piece thoroughly before serving.