Rinse the quinoa thoroughly under cold water.
Add quinoa and water to a medium saucepan. Bring to a boil, reduce heat to low, cover, and simmer for 15 minutes. Remove from heat and let rest for 5 minutes before fluffing with a fork.
In a large bowl, combine ground turkey, breadcrumbs, egg, oregano, garlic powder, salt, and black pepper.
Mix gently until just combined and form into evenly sized meatballs about 1½ inches in diameter.
Heat olive oil in a large skillet over medium-high heat.
Add meatballs and cook for 2–3 minutes per side until deeply golden brown and cooked through.
Divide cooked quinoa among serving bowls.
Add mixed greens over the quinoa.
Arrange five turkey meatballs in each bowl.
Add cherry tomatoes, cucumbers, and red onion around the meatballs.
Sprinkle with feta cheese and Kalamata olives.
Top with a generous spoonful of tzatziki sauce.
Finish the Greek Turkey Meatball Bowls with fresh dill and cracked black pepper before serving.