Preheat the oven to 400 degrees F. Line a large baking sheet with parchment paper. Set aside.
Use a mesh strainer to drain the liquid from the grated zucchini. Press down onto the zucchini in the strainer until all or most of the liquid comes out.
In a large bowl combine ground turkey, olive oil, minced garlic, eggs, Italian seasoning, salt and pepper, zucchini and onion. Mix well using your hands until the ingredients are well combined. Scoop 2 tablespoons sized meatballs from the mixture and roll into a firm ball. Place onto the prepared baking sheet, repeat with the remaining meat.
Place into the oven and bake for 20-25 minutes or until evenly browned and cooked through (the internal temperature has reached 165 degrees F.).
While the meatballs are baking, prepare the sauce. Warm 3 tablespoons of olive oil over medium-high heat. Add garlic and sauté for one minute. Add the crushed tomatoes, salt, pepper, sugar, Italian seasoning, and red pepper flakes. Stir until well combined. Simmer for 15 minutes, stirring occasionally.
When the meatballs are done baking, add them to the sauce and stir to coat.