Preheat the air fryer to 400F/200C. While it's preheating, season the salmon with salt and pepper and sprinkle the zest of half a lemon all over.
Once the air fryer is preheated, arrange the salmon in the basket of the air fryer and spray it with a cooking spray. (If you choose to use oil instead of the spray, brush the salmon with 1 tsp of olive oil, then season with salt, pepper and lemon zest.) Cook for 8 minutes.
While the salmon is cooking, in a small bowl, mix the mayonnaise with the zest and juice of ½ lemon, mustard and chopped dill to make the sauce.