Sprinkle both sides of the salmon with kosher salt. Let the salmon sit for 5 minutes while you mix the spices in step 2.
In a small bowl, mix mayo, avocado oil, garlic powder, paprika, and black pepper until combined.
By now you should see excess water pooling up on the salmon. Pat dry and flip the filet over, then run a sharp knife over the salmon skin to draw out moisture and remove excess scales (skip this step if are using skinless salmon), then pat both sides of the salmon completely dry with a paper towel. Place the salmon skin side down and rub the marinade on the flesh side only.
Spray the air fryer basket with a neutral oil spray. Place the salmon side down and air fry at 400F for 8-12 minutes depending on the thickness of the salmon. After the 8 minutes of cooking, check the salmon in 1 minute intervals after 8 minutes until the salmon reaches 145F.
Video
Notes
I used 5oz pieces. Ask your butcher to cut the salmon into 5oz filets or use a kitchen scale and cut them yourself at home. If you use smaller or larger (thicker) pieces, you will need to adjust the cooking time in proportion to the size. I have instructions on how to do this in the recipe notes!Using a binder like mayo provides a little layer of protection around the salmon and prevents it from drying out, while adding tons of flavor!Running a knife along the skin allows additional moisture to draw out which results in a crispy skin.The cooking time will vary widely on the type of salmon and thickness of the filet. I used wild Alaskan salmon here and 8 minutes at 400°F was consistenly perfect. For a farm raised salmon that may be a thicker filet, ensure that you are checking the temperature very 1 minute after the 8 minute mark until the salmon reaches 145°F - it will overcook quickly so be mindful of this!Storage, Reheating, and Make Ahead Tips - You can make the spice paste in advance, but ensure that you do not skip salting the salmon in step 1. This is essential to making sure the salmon is fully seasoned throughout and will help keep it moist. For reheating, I suggest air frying at 350°F at for 3-5 mintues or until warmed through.