In a medium bowl, combine all marinade ingredients. Cut turkey into 1½-inch cubes and thoroughly mix with the marinade. Cover and refrigerate for 2-4 hours. Meanwhile, combine yogurt-mint sauce ingredients and keep cold until ready to serve.
If using wooden skewers, soak them in water for at least 20 minutes before grilling. Preheat charcoal grill to medium-high, direct heat cooking. Meanwhile, thread marinated turkey onto skewers (presoaked if using wood) and lightly brush with oil. Grill for 3-4 minutes per side or until internal temperature reaches 160-165° Fahrenheit. Take skewers off heat and loosely tent with foil to rest for 5 minutes. Meanwhile, heat pita bread (or naan) in a 400° oven for about 3 minutes, or until heated through.
Serve souvlaki with pita bread, yogurt-mint sauce, tomato, onion and lemon wedges.