Preheat the air fryer to 380°F (around 193°C).
Pat the salmon fillets dry with paper towels and place them skin-side down on a plate or cutting board.
In a small bowl, combine 2 teaspoons Cajun seasoning with 1/2 teaspoon salt and 1/4 teaspoon freshly ground black pepper.
Drizzle the fillets with 1 tablespoon olive oil, then sprinkle the seasoning mixture evenly over all sides, pressing gently to adhere.
Lightly spray or brush the air fryer basket with cooking spray and place the fillets in the basket skin-side down, leaving space between them for air circulation.
Air fry at 380°F for 8 to 10 minutes, flipping once halfway through, until the salmon flakes easily with a fork and reaches 145°F in the thickest part.
Remove the fillets from the air fryer and let rest briefly before serving.