Preheat a 6-quart air fryer to 390°F for 3 minutes. Thoroughly dry thighs, especially skin; unfold without removing skin.
Rub meat sides with zest, pepper, garlic powder, and half the salt. Lightly rub skin with oil and remaining salt.
Air fry skin-side down 7 minutes. Turn skin-side up; cook 8 to 11 minutes more until skin crisp and thickest meat at least 165°F.
Plate skin-side up; rest uncovered 5 minutes. Spoon lemon juice around cut meat edges, not over crisp skin.
Serve one thigh per person while skin stays crisp.