Prepare your grill for cooking over high direct heat.
In a medium bowl combine all the lamb burger patties ingredients together and mix everything together until everything is well incorporated. Divide the meat in 4 and form into burger patties.
Place the patties on the grill and cook for about 5 minutes per side. DO NOT press on the patties while cooking. 2 Minutes before the patties are done cooking, add the burger buns to the grill and grill them for about 30 seconds.
Remove everything from the grill and assemble the burgers. Start with adding some baby arugula to the bottom of the bun, then the burger patty, followed by a couple tbsp of tzatziki sauce, some crumbled feta cheese, tomato slices, cucumber slices and red onion slices. If you prefer you could add more tzatziki sauce to the top bun.
If you don't like lamb, ground beef will still be great in this recipe.
Tzatziki is a sauce made with plain yogurt, cucumbers, garlic, and dill. You can make it yourself, or find it at your local grocery store.