In a small bowl, mix together all the garlic yogurt sauce ingredients. Taste, and adjust seasoning as needed, then set aside in the fridge.
In a large bowl add all the turkey burger ingredients (except for the buns), then mix together until fully combined. Then transfer to the fridge for 30 minutes and allow the meat to marinate. This will help the patties hold their shape and increase flavor.
Remove the turkey mixture from fridge, and shape into 4 burger patties.
Heat a skillet over medium-high heat and drizzle with olive oil (or you can cook them on a grill). Then grill/sear the burgers for 4-5 minutes per side, or until internal temp reaches 165°.
Let the burgers rest for 2-3 minutes. While they rest, mix together the arugula, feta, salt, pepper, lemon juice, and EVOO (all to taste).
Toast your buns. Then assemble the burgers by adding some garlic yogurt sauce on the bottom and top bun. Then add the burger on the bottom bun, followed by a small handful of the arugula salad. Top with the top bun and enjoy!