In a large bowl mix the Greek yogurt, lemon zest, lemon juice, grated garlic, oregano, dill salt and pepper. Add the boneless skinless chicken breast and stir to coat the chicken in the yogurt marinade. Let the chicken marinate for at least 1 hour or up to 4 hours in the refrigerator.
While the chicken is marinating mix together the red wine vinegar, olive oil, oregano, fresh dill, salt and pepper. Add the chopped tomatoes, cucumbers, olives, and red onions. Stir to coat the vegetables in the vinaigrette. Chill in the refrigerator until ready to serve.
Preheat grill to 450℉. Use a wadded paper towel dipped in oil to grease the grill grates. Add the chicken to the hot grill shaking off as much excess marinade as possible.
Grill for 7-8 minutes so the chicken has time to brown and achieve good grill marks. Carefully flip the chicken and grill for another 7-8 minutes or until the chicken reaches 165℉when tested with a meat thermometer.
Once the chicken is removed from the grill, set aside to allow the meat to rest for about 5 minutes before slicing.
Divide the rice among four bowls, then top with the tomato salad, tzatziki, and sliced grilled chicken. Garnish with crumbled feta cheese and extra fresh dill if desired.