Pat the salmon fillet dry with paper towels, ensuring the skin is clean and free of moisture for crispiness.
Lightly brush the entire surface of the salmon with olive oil, covering all sides to help the pepper and seasonings adhere.
Generously sprinkle cracked black pepper over the top and sides of the fillet, pressing gently to ensure it sticks and forms a thick crust.
If using, sprinkle lemon zest, salt, and paprika evenly over the seasoned fillet for added flavor and color.
Place the seasoned salmon fillet, skin-side down, into the air fryer basket lined with parchment or a silicone mat to prevent sticking.
Set the air fryer to 400°F (200°C) and cook for 12 minutes, until the crust is crispy and golden, and the flesh feels firm but still moist when pressed.
Carefully remove the salmon from the air fryer, and let it rest for a minute to settle the juices.
Garnish with freshly chopped herbs for a burst of color and freshness, then serve immediately to enjoy the crispy crust and tender interior.