In a large mixing bowl, add in ground turkey/chicken, red onion, egg, bread crumbs, garlic cloves, salt, pepper, cumin, oregano, and lemon zest. Mix well until combined.
Roll out 1-inch meatballs.
Heat a cast iron skillet over medium heat, add the oil, and heat for 1-2 minutes. Add the meatballs, with space in between, and cook for 8-10 minutes, or until golden brown and cooked through.
For the Tzatziki Sauce:
In a small bowl, mix together Greek yogurt, lemon juice, fresh dill, cucumber, salt, and pepper.
Taste test for seasonings, add more salt and pepper if needed, cover, and refrigerate until bowls are ready to assemble.
For the Pickled Red Onions:
To quick pickle your red onions, thinly slice red onion and place into a large mason jar.
Pour apple cider vinegar, sugar, and Kosher salt.
Shake jar vigorously and place into the refrigerator for 1 hour. Will keep for 2 weeks.
To Assemble the Bowl:
Assemble each bowl with a bed of greens and a small scoop of cooked quinoa.
Top with cooked Greek meatballs, Tzatziki, pickled red onions, cherry tomatoes, cucumbers, and Feta cubes.