Preheat the air fryer to 375°F (190°C).
In a large bowl, combine all the ingredients for the meatballs, and mix together using your hands. Roll the beef mixture into even-sized balls the size of a walnut. In batches, cook the meatballs in the air fryer basket in a single layer for 8-10 minutes, or until cooked through.
In the meantime, add the tomato to a large bowl with the salt and stir through the remaining ingredients. Refrigerate until ready to serve.
Place the grated cucumber into a medium bowl with the salt for the tzatziki sauce. Set aside for 2 minutes, then drain off any excess water. Mix in the remaining ingredients, then cover and refrigerate until ready to serve.
When the meatballs have finished cooking, assemble the plates. Divide the meatballs equally and serve with a portion of the tomato salad, tzatziki and toasted pita bread.