In a large bowl, combine the olive oil, paprika, cumin, garlic powder, onion powder, black pepper, salt, and cayenne pepper (if using). Mix well to create a spice paste.
Add the chicken thighs to the bowl and coat them thoroughly with the spice mixture. Let it marinate for at least 10 minutes for better flavor.
Preheat the air fryer to 200°C (400°F). Place the marinated chicken thighs in the air fryer basket in a single layer. Cook for 15-20 minutes, flipping halfway through, until the chicken is golden brown and cooked through.
While the chicken is cooking, prepare the tahini drizzle by mixing tahini, lemon juice, and enough water to achieve a smooth, pourable consistency.
Once the chicken is done, remove it from the air fryer and let it rest for a few minutes. Drizzle the tahini sauce over the chicken and garnish with fresh parsley before serving.