Trim and pat dry: Trim excess fat from the thighs. Pat them dry with paper towels so the rub sticks and browns well.
Mix the rub: In a small bowl, combine salt, pepper, paprika, garlic powder, onion powder, oregano, and chili powder (if using). Add lemon zest for brightness.
Season the chicken: Toss thighs with olive oil, then coat evenly with the spice mix.
Drizzle in half the lemon juice. Let sit 10–20 minutes at room temp, or refrigerate up to 12 hours.
For Air Fryer: Preheat to 380°F (193°C) for 3–5 minutes.
Lightly spray the basket. Arrange thighs in a single layer.
Cook 12–16 minutes, flipping halfway, until the thickest part reaches 165°F (74°C).
Thicker pieces may need a minute or two more.
Rest 5 minutes, then squeeze over remaining lemon juice.
For Grill: Preheat grill to medium-high (400–425°F). Clean and oil the grates.
Grill thighs 5–7 minutes per side, lid closed, until charred in spots and internal temp hits 165°F (74°C).
Move to indirect heat if browning too fast. Rest 5 minutes and finish with lemon juice.
Garnish and serve: Sprinkle with chopped parsley or cilantro.
Serve with rice, roasted veggies, salad, or stuffed into warm pitas.