Coat a large Dutch oven with the olive oil and set over medium heat. When the oil forms a little haze, add the bell peppers, tomatoes, onions, and garlic; cook and stir for about 7 minutes until the vegetables are soft, but not browned. Add the ham and sausage and stir for 2 minutes to release some of the flavorful fat. Stir in the paprika, pepper flakes, bay leaves, and wine. Simmer and stir for 10 minutes to cook down the liquid a bit. (If using a cataplana, transfer the sauce into the vessel, and proceed as directed.)
Lay the clams in the sauce and toss with a large spoon so they are well coated and some of the sauce is on the top. Squeeze in the lemon juice and shower with chopped parsley. Tightly close the Dutch oven or cataplana and simmer over moderate heat for 15 minutes until the clams open ¿ no peeking. Discard any clams that haven't opened at that point. Remove the cataplana from the stove and open it at the table. Ladle into soup bowls and serve immediately with crusty Portuguese bread.