How to Make It
In a large pot, heat the oil over moderately high heat. Add the sausage; cook, turning, until browned, about 10 minutes. Remove. Pour off all but 2 tablespoons fat.
Reduce the heat to moderately low. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes. Add the garlic and paprika and cook, stirring, for 30 seconds longer. Remove from the heat. Cut the sausage into 1/2-inch slices and stir them and the tomato paste into the pot.
In a medium stainless-steel saucepan, combine the clam juice, wine, bay leaves, and red-pepper flakes. Discard any clams that are broken or do not clamp shut when tapped. Add the clams to the pan. Cover and bring to a boil. Cook, shaking the pan occasionally, until the clams open, about 3 minutes. Remove the open clams and continue to cook, uncovering the pan as necessary to remove the clams as soon as they open. Discard any that do not open.
Carefully pour the clam-cooking liquid into the sausage mixture, leaving any grit in the bottom of the pan. Add 2 tablespoons of the parsley, salt if needed, and the black pepper. Bring to a simmer, cover, and continue simmering for 5 minutes. Stir in the clams in their shells. Simmer, covered, just until the clams are warm through, about 1 minute. Serve topped with the remaining parsley.