Mix all the meatball ingredients together in a large bowl. Using wet hands, shape the meat mixture into 1-inch meatballs by rolling it between your hands until it forms a ball. This should make about 35 meatballs, depending on how big you make them. Keep them in the refrigerator until ready to add to the soup.

In a large, heavy pot, heat the olive oil over medium heat. Add onions and cook until softened, about 2-3 minutes. Add the garlic, chopped carrots, celery, and potatoes and cook, stirring frequently, for about 5 minutes, or until they start to soften. Pour in the chicken broth, water and can of tomatoes. Stir in oregano and cumin. Bring to a boil over high heat, then reduce heat to medium-low, cover, and let simmer for about 5 minutes.

Add the meatballs to the simmering soup, one at a time. Stir very gently, to avoid breaking apart the meatballs. Cover and simmer over medium-low heat for another 10 minutes. Stir in zucchini and cook, until soft, about 10 minutes. Stir in the lemon juice, and season with salt and pepper, to taste. Serve.

Garnish with chopped fresh parsley.