Grate cucumber, and then squeeze and drain in colander.
To make tzadiki sauce, conbine grated cucmber with the remaining Tzadiki ingredients: yogurt,salt, pepper, lemon juice and olive oil. Set aside.
For burgers, combine ground turkey, seasonings and feta in a medium bowl and mix (with your hands!).
Divide turkey mixture into six even balls and flatten. Using wet hands to do this makes the job much easier!
Fry burgers in a medium skillet over medium heat, or grill on barbeque.
Assemble burgers on bun with tzadiki, lettuce, tomato, onion. Enjoy!