1. Whisk together olive oil, lemon juice, garlic powder, and dill in a small bowl.
2. Place tuna belly in a shallow non-reactive baking dish that can fit inside the Air Fryer basket. Drizzle with olive oil mixture, making sure to coat all side. Season with salt and pepper to taste.
3. Preheat your Air Fryer to 400 F.
4. Cook the tuna for 15 minutes or until golden brown, turning halfway through cooking time.