Preheat a grill pan on medium heat. Season the chicken on both sides with seasoning rub on both sides. Grill the chicken on both sides to get nice caramelized markings. The transfer the pan to the oven and cook to an internal temperature of 160 degrees using a thermometer. Let rest for 5 minutes before cutting into bite sized pieces.
In a bowl, mix together the chicken, oil, vinegar, lemon juice, celery, onion, cucumber, olives, tomatoes, and feta. Season with salt and pepper to taste. Be careful not to add too much lemon.
Place the mixture on the wrap, fold in one or both ends and roll up tightly.