@Entryhazard nope, mochi is mochi. It's a traditional rice based sweet sometimes refered as rice cakes. It's normally eaten on New Year's and causes a couple suffocation deaths yearly.
Rice is smashed until it's very sticky and consistent. It can be served as is or with a filling of anko (red bean paste), or maybe some less traditional fillings like strawberry.
But fruit sashimi is so far from reality that it's not even funny. Sashimi is raw fish sliced thin, what would fruit sashimi even be? What drug did the translator use when writing that?