Add oil to large saucepan over medium heat. Add the fennel, carrot, garlic, and red onion. Saute about 5 minutes. Add the chorizo and cook until chorizo is almost done.
Add chicken stock and tomatoes. Bring to a boil and reduce to a simmer and simmer 15 minutes.
Meanwhile mix the chicken with ground fennel and lemon zest. Season with salt and pepper. Add the orzo to soup mix. Drop the chicken mixture by spoonfuls in hot soup. Cook for another 10 minutes or until pasta is cooked.
Stir in the spinach and cilantro. Taste and season with salt and pepper. Top with Parmesan cheese to serve