Preheat oven to 175°C, 347°F and lightly grease baking tray.
Shred courgette and kale.
In a mixing bowl, combine the ground beef, crumbled feta cheese, olives, egg white, oregano, black pepper and cumin and form into meatballs. Place on a baking tray and cook for 18 to 22 minutes or until no longer pink in the middle.
Meanwhile, heat olive oil in a skillet over medium heat. Add the courgettes and kale and saute; for 3-4 minutes until tender. Season with salt (optional) and pepper to taste.
Heat tomato sauce in a pan.
Serve the meatballs with tomato sauce over the top with the courgettes and kale on the side.