Preheat oven to 375 degrees.
In a small bowl, combine yogurt, juice of 1/2 lime, 1 tsp cumin, 1/2 tsp paprika, 1/4 tsp dill and 1/2 tsp kosher salt. Remove 1/4 cup of the yogurt mixture and add to turkey. Refrigerate remaining yogurt mixture.
To turkey and 1/4 cup yogurt mixture, add remaining garlic powder, paprika, dill, turmeric and cumin. Add grated onion and 1 tsp salt.
Divide meat into 20 meatballs. Place meatballs on an oiled sheet pan. Toss the onion slices with a dash of salt and a drizzle of oil. Sprinkle the sliced onion on the pan as well.
Roast meatballs in the oven until 165 degrees or 11-14 minutes. Remove the meatballs from the oven and squeeze 1/2 of a lime over them.
Slice cucumbers into thin coins, and chop herbs for garnish.
Serve meatballs and onions on pitas with reserved yogurt and cucumber slices. Garnish with fresh mint or parsley.