1. Preheat oven 350°F. Arrange meatballs on an oil-coated sheet pan. Bake for 15 to 20 minutes until heated through.

2. Mix all Tzatziki Sauce ingredients together in a small bowl and set aside.

3. To assemble, spread hummus on the pitas, and then divide and arrange meatballs, salad greens, onions and tomatoes on top of the hummus.

4. Top with Tzatziki Sauce and serve immediately.