Preheat oven to 425 degrees. Drizzle a large oven-safe skillet or baking dish with olive oil.
In a large bowl combine all ingredients (except for olive oil, tzatziki sauce, cucumbers and tomatoes) and mix well. Shape into 1 1/2 inch balls and place in prepared skillet or baking dish.
Bake for 20 minutes or until browned and cooked through the center. Serve meatballs gyro-style wrapped in a pita with tomatoes, lettuce, and tzatziki sauce, or serve meatballs alone for a grab-n-go meal.