In a medium bowl combine ground chicken with ingredients listed, except feta cheese and olive oil.
Mix well.
Divide mixture into 2 portions(these make large patties).
Flatten ground chicken mixture in your palm
Place a cube of feta in the middle of the chicken and wrap meat around cheese, forming a patty.
Pour the olive oil onto a plate and place chicken patties on the plate, flipping over to coat the burgers with the oil. (Oiling your patty prevents the chicken burger from sticking to BBQ grill).
Heat BBQ to medium heat and cook chicken burgers for 15-20 minutes.
Remove burgers from BBQ. Place the burgers on a large lettuce leaf, then top with tzatziki sauce (see below) and a large heirloom tomato.
Wrap lettuce leaf around your chicken burger and enjoy!