Put the clams in a large pot or Dutch oven with 1 cup water. Cover and cook over medium-high heat until the clams start opening, about 5 minutes; as the clams open, transfer them to a bowl using tongs. (Discard any unopened clams.) Add the cooking liquid to the bowl with the clams (strain through a paper towel-lined sieve if sandy). Cover to keep warm.
Wipe the pot clean and reduce the heat to medium. Add the olive oil and chorizo. Cook, stirring occasionally, until the chorizo is lightly browned, about 3 minutes. Add the leek, bell pepper, garlic and bay leaves. Cook, stirring occasionally, until the vegetables are tender, about 4 minutes. Add the rice; cook, stirring, until lightly toasted, about 2 minutes. Add the chicken broth and 1 cup water; bring to a boil, then reduce the heat to medium. Cover and simmer, stirring once or twice, until the rice is tender, about 15 minutes. Discard the bay leaves.
Meanwhile, puree the parsley with 1/3 cup water in a blender until smooth. Stir the lima beans, parsley puree, and the clams and their juices into the rice mixture. Cook until the lima beans are tender, 3 to 4 minutes.