Preheat the air fryer to 390°F for 3 minutes if recommended by the manufacturer.
Pat the chicken dry, trim loose fat and open each thigh flat. Sort markedly different sizes into groups.
Combine paprika, garlic powder, onion powder, oregano, salt, black pepper and optional cayenne.
Toss the thighs with oil, then rub the seasoning evenly over both sides and into the natural folds.
Place the thighs smooth side down in one layer with visible space between them.
Cook at 390°F for 7 minutes. Turn and cook for 5 to 8 minutes longer, removing individual pieces as their thickest point reaches 165°F.
Transfer the chicken to a clean plate and rest for 3 to 5 minutes. Add lemon and parsley if desired.
