Wash clams thoroughly, discarding any opened shells. Set aside.
Remove beards on mussels and scrub mussel shells well with a brush. Discard opened, cracked, or heavy mussels. Set aside.
Heat oil in a 17-inch paella pan. Add chicken and cook over medium coals, until chicken is golden and juices run clear. Add garlic and onion and cook until crisp-tender. Add chorizo and cook until thoroughly heated. Add rice and cook, stirring constantly, until grains are coated with oil. Add tomatoes, chicken broth, saffron threads, wine, and green beans. Bring to a slow boil. Cook 20 to 30 minutes, stirring occasionally. Add additional water as needed. Add seafood and cook 15 additional minutes, or until prawns turn pink and mussels and clams open.