Clean the clams and soak in cold water for 20 minutes.
Transfer the shrimp to a bowl and season with 1/2 tablespoon lemon juice and Old Bay.
Heat a large, deep nonstick skillet over medium heat.
Add 1 teaspoon of oil and sauté the chorizo, onions, garlic and paprika until soft, about 3 minutes.
Push aside, add the remaining 1 1/2 teaspoons oil in the center and add the rice, stirring to coat with the oil. Sauté 3 minutes.
Add the diced tomatoes, broth, salt, saffron threads (crumbled between fingers) and bay leaf.
Mix and bring to a boil, stirring once, place the bell pepper over the rice, reduce heat to low and cover tightly, cook 15 minutes. Uncover, add the clams, shrimp and peas.
Cover tightly again and cook on low heat until the clams open up and the shrimp are cooked through, about 10 to 12 minutes.
Uncover the skillet, raise the heat to medium-high and cook to toast the bottom of the rice, you should hear it sizzling, about 2 to 3 minutes.