The Silken tofu is a silky soft tofu variety from Japan. The texture resembles that of pannacotta. Silken tofu contains more water (and therefore fewer calories and nutrients) than regular tofu and generally doesn't have that typical soy flavor that some people don't like.
How to use?
Carefully drain the Silken tofu on a chopping board, possibly with some kitchen paper and a weight (other chopping board) on top. Carefully dice it and then eat it raw in a salad or warm it up in soup, sauce, with noodles or rice. A classic Japanese dish is agedashi: cubes of silk tofu dusted with flour, fried and served in a sauce/soup based on dashi. Vegans use silken tofu instead of cream, milk or egg in sauces, dressings and desserts.
Note: Make sure that the soup/sauce is already ready and tasty so you don't have to stir, as the cubes already fall apart when you look at them.