Preheat the Air Fryer: Set your air fryer to 400°F (200°C) and allow it to preheat for about 5 minutes.
Prepare the Marinade: In a small bowl, whisk together the olive oil, lemon juice, garlic powder, dried oregano, dried basil, red pepper flakes, salt, and pepper until well combined.
Marinate the Salmon: Place the salmon fillets in a shallow dish or a zip-lock bag. Pour the marinade over the salmon, ensuring each fillet is coated well. Let it marinate for at least 15 minutes while you prepare the other ingredients.
Prepare Vegetables: In another bowl, combine the halved cherry tomatoes and chopped spinach. Drizzle with a little olive oil, salt, and pepper, and toss to coat. Set aside.
Arrange in Air Fryer: After marinating, place the salmon fillets in the air fryer basket lined with parchment paper, ensuring there's space between each fillet. Top each fillet with the tomato and spinach mixture, then sprinkle the grated Parmesan cheese evenly over the top.
Air Fry: Cook the salmon in the air fryer for 8-10 minutes. Check for doneness—salmon should flake easily with a fork and have an internal temperature of 145°F (63°C). The Parmesan should be golden and bubbly.
Serve: Carefully remove the salmon from the air fryer. Garnish with fresh basil leaves, if desired. Serve the salmon warm with your favorite side dishes, such as a salad or roasted vegetables.