Sambal is a hot sauce made of ginger, chili peppers, shrimp paste, shallot, scallion, and other ingredients. De-shelled blood cockles smothered in a thick and fiery sambal is popular dish among Malay community in Malaysia and Singapore. The gravy of sambal blood cockles is best when drizzled on a serving of steaming hot rice.
However, unlike other varieties of clams that are safe to eat, the blood clams live in low-oxygen environments, and thus ingests more viruses and bacteria, so it's strongly advised to quick-boil them before preparing the dish. By the way, the're called blood cockles because they have this blood-like red liquid inside their soft tissues.