I can’t help but picture Polonius laid out on a dining room table – naked and covered in sushi, like one of those weird specialized models that people eat sushi off of.
I can’t believe that that is a thing.
But I know that it is
And this line evokes that for me.
It starts with the sushi sitting on top of him and once the gleeful mob has eaten all the rolls it can manage, they break out the knives and forks and start carving into the dish – i.e. carving into the dead naked Polonius. Yum. (Yuck.)