- Make the broth: Heat olive oil in a small stockpot over medium heat. Add fennel, onions, celery, garlic, and red pepper flakes. Sauté until vegetables have softened, about 5 minutes. Add tomatoes and cook 5 minutes, then add white wine and cook for 5 minutes more. Add stock, paprika, salt, and pepper and simmer over medium heat until reduced by a quarter and all flavors are incorporated, about 30 minutes.
- Prepare the shrimp and clams: Heat olive oil in a deep, wide pan. Add chorizo and cook for 5 minutes, browning lightly. Add shrimp and clams and season with salt and pepper. Sauté for another 3 to 4 minutes, tossing seafood in chorizo oil, then add white beans and prepared tomato-fennel broth. Cover and simmer over low heat until all clam shells are open and shrimp is cooked, about 5 to 10 minutes. Season to taste. Discard any unopened clams and serve in a large bowl, garnishing with chopped fresh parsley, a drizzle of olive oil, and a squeeze of fresh lemon juice.