For the tzatziki, place the grated cucumber in the center of a clean kitchen towel. Roll up the towel and squeeze out the excess water from the cucumber. Place the cucumber in a medium bowl. Add the yogurt, garlic, salt, pepper and lemon juice. Stir to combine. Cover and refrigerate until ready to serve. This can be made several days in advance.
MEATBALLS:
In a medium bowl, stir together the bread crumbs and milk and let the mixture sit for a few minutes to let the crumbs soften. Add the parsley, egg, oregano, garlic, salt, and pepper. Stir to combine. Add the turkey and mix until well combined.
Using a cookie scoop or spoon, form the mixture into meatballs and place them into a sprayed air fryer basket. You can make the meatballs whatever size you want, however I recommend about 1-2 tablespoons of mixture for each meatball.
Cook for 10-15 minutes at 350 °F.
TO SERVE
To serve, slice the pita breads in half. Dollop a spoonful of tzatziki sauce on the bottom of each pita. Add a layer of tomatoes and greens. Stuff meatballs inside and serve.