In a large mixing bowl or a Ziploc bag, whisk together the olive oil, lemon juice, lemon zest, yogurt, vinegar, onion, garlic, thyme, oregano, paprika, coriander, and black pepper. Marinate at room temperature for 30 minutes to 1 hour or place in the refrigerator to marinate for up to 24 hours.
Heat an indoor or outdoor grill, and lightly brush the grates with a high-heat oil such as canola or grapeseed. When the grill is hot, add the chicken and grill until the chicken reaches an internal temperature of 160 degrees Fahrenheit (71 degrees Celsius). Remove from grill, transfer to a dish, cover with foil, and allow to rest for 5 minutes before using.
To assemble: Add your favorite toppings to the pita bread, wrap, and serve.
Notes
STORE leftover Grilled Greek Chicken Pitas in an airtight container in the refrigerator for up to 3 days. For longer storage, FREEZE the marinated chicken (uncooked) for up to 2 months. Reheat the chicken in a skillet over medium heat or in the oven at 350°F (175°C) until warmed through.Avoid reheating in the microwave to prevent the chicken from becoming rubbery. Assemble pitas with fresh toppings just before serving for the best taste and texture.