Washing meat is pretty common in Chinese cooking. It’s not done over the tap however. Meat is fully immersed in cold water and soaked for a while, then pulled out, squeezed to drip-dry, then the water discarded. This helps to wash off any juices or blood and results in a cleaner taste. It can also help improve marinade results and further improve flavour (ostensibly by reducing the amount of off flavours).