Cut the zucchini lengthwise and grate enough until you have 130 grams (about 1 cup packed).
Place zucchini in a colander over a small bowl, stir in salt, and let it sit for a few minutes to draw the liquid. Set aside.
Meanwhile, combine the egg, feta, garlic, green onions, smoked paprika, cumin, and cayenne pepper in a large mixing bowl.
Press zucchini with the back of a spoon to release liquid, discard liquid, and stir zucchini into egg mixture.
Add ground turkey and mix until just combined.
Preheat air fryer to 400°F.
Scoop mixture with a 2-tablespoon cookie scoop to create golf ball-sized rounds. Freeze for 20 minutes to set.
Roll the feta turkey meatballs between your hands to reshape if needed.
Lightly spray the turkey feta meatballs, and arrange them in a single layer in the air fryer basket (leaving space between them). Cook in batches for about 8 minutes, or until an instant-read thermometer registers 165°F. Keep cooked meatballs warm in the oven until all air fryer turkey meatballs are finished.
Serve with tzatziki sauce or combine turkey meatballs and rice together with cucumber slices and tomatoes for a complete meal.