Preheat your air fryer to 400°F (200°C) for 3–5 minutes. A hot basket helps the salmon sear and the asparagus roast properly.

Pat the salmon dry. Use paper towels to remove surface moisture. This helps the seasoning stick and encourages light browning.

Season the salmon. In a small bowl, mix lemon zest, paprika, 1/4 teaspoon salt, and black pepper. Brush the tops of the fillets with 1/2 tablespoon olive oil, then sprinkle the seasoning mixture evenly. If using garlic powder, add a pinch here; if using fresh garlic, save it for the asparagus.

Toss the asparagus. In a bowl, combine asparagus with the remaining 1/2 tablespoon olive oil, lemon juice, minced garlic (if using), and a pinch of salt and pepper. Coat evenly.

Arrange in the basket. Place the salmon fillets in the air fryer basket, skin side down if they have skin. Arrange asparagus around the fillets in a single layer as much as possible. Avoid crowding; work in batches if needed.

Air fry. Cook at 400°F (200°C) for 7–10 minutes, depending on salmon thickness and your preferred doneness. Thin fillets may be ready at 7 minutes; thicker ones might need 10–12. The asparagus should be crisp-tender with lightly browned tips.

Check doneness. Salmon is done when it flakes easily and reaches an internal temperature of 125–130°F for medium (juicy) or 140°F for more well done. If asparagus needs more time, remove the salmon to a plate and cook the asparagus for 1–2 additional minutes.

Finish and serve. Squeeze extra lemon over everything, sprinkle with fresh dill or parsley, and add red pepper flakes if you like heat. Serve immediately.