I suppose if you had to teach kids where sushi comes from, these cushions by Mutsumi Kozasa would be the most children-friendly way to go.
The Bara-Bara Fishery cushions by Mutsumi Kozasa are a series of pillows of anatomical fishes. These aquatic animals definitely look like they're being prepared for sushi since their whole body is cut-up revealing body parts and bones leaving the head and the tail as the only non-exposed parts. It's kind of grim and even a bit morbid but the cartoon quality helps make them amusing and at least it's not grotesque to the point where kids can't see it.
Check out the Bara-Bara Fishery cushions by Mutsumi Kozasa for a slightly grotesque, yet surprisingly funny sashimi-inspired pillow in the gallery.