Place the salmon on a foil sling and surround it with the peppers and onions in the air fryer basket. Lightly spray with avocado oil and massage salmon with fajita seasoning.
Cook in the air fryer basket at 350°F/175°C for 8-10 minutes, or until salmon flakes easily and registers at 145˚F/62.8˚C (thinner salmon will be ready sooner, thicker salmon will take more time).
Remove the contents from the air fryer basket and serve on tortillas with avocado, salsa, lime, coleslaw, etc.