Place the chicken and shrimp in a bowl, and generously season with the Spanish spice rub. Cover, and refrigerate for at least 30 minutes, or up to 2 hours.
Place 3 tablespoons of oil in a deep skillet (or, use a paella pan if you have one). Heat to medium high, then add the chicken and shrimp. Remove the shrimp to a bowl when it turns pink - about 2-3 minutes. Remove the chicken to a bowl when browned, about and additional 2-3 minutes.
Place the chorizo in the pan, and cook until browned - about 3-4 minutes. Transfer the chorizo to a bowl.
Add the tomatoes and green beans, and salt and pepper lightly. Saute for 3 to 4 minutes. Add the additional olive oil, then add the tomato paste. Cook, while stirring, for 2 minutes. Add the garlic and any remaining spice rub, then cook for about 30 seconds. Add the sherry and cook until most of the liquid has evaporated.
Add the broth, rosemary, bay leaves, and optional saffron. Add back the chicken and chorizo. Bring the liquid to a boil, then sprinkle the rice into the skillet, distributing the grains evenly. Press the rice to make sure it's all submerged in the broth. Cook on medium for 10 minutes.
Add the shrimp. Remove the pan from the heat, and cover for 5 minutes. You are ready to serve!