Soaps does not directly kill bacteria, it dissolves the fatty membrane of viruses and they fall apart like a house of cards. Bacteria can live in a watery environment, and the bubbles of soap suds trap the bacteria and wash them away. After using the soap, rinse it and let it dry until next use.
The natural soaps don't create as much foam as others because they don't contain synthetic foaming agents, but their washing properties are just as good.