In a bowl whisk the ingredients for the marinade. Season with salt and pepper.
Brush the chicken with the marinade on both sides. Brush the bread with the marinade as well.
Mix the tomatoes, cucumber, onion, olives, feta, oil, oregano, and white vinegar.
Grill the chicken on both sides getting nice char marks to an internal temperature of 160 degrees using a thermometer, brush the chicken with the marinade throughout cooking. Once cooked set aside to rest for 5 minutes.