Spray the air fryer rack with non-stick cooking spray (I use avocado oil spray).
Pat the fish dry and cut into sticks about 1 inch by 2 inches wide (how you are able to cut it will depend a little on what kind of fish you by and how thick and wide it is).
In a small shallow bowl, whisk together the mayo, mustard, and water. In another shallow bowl, whisk together the pork rinds and Cajun seasoning. Add salt and pepper to taste (both the pork rinds and seasoning could have a fair bit of salt so dip a finger in to taste how salty it is).
Working with one piece of fish at a time, dip into the mayo mixture to coat and then tap off the excess. Dip into the pork rind mixture and toss to coat. Place on the air fryer rack.
Set to Air Fry at 400F and bake 5 minutes, the flip the fish sticks with tongs and bake another 5 minutes. Serve immediately.