1Lay out the fish, shiso and cucumber in strips. Season with salt and yuzu zest.
2Next roll them up , cut them in half for 2 chunky "barrels" Arrange in shallow bowl and add chilled dashi. Shiso oil drizzled on top is a nice touch! As are olives which are totally not Japanese and totally work!
For a nice firm texture on your fish, season with salt 20 minutes before preparation or take it to a higher level altogether by pressing the fish for an hour or more with kombu.
It is best to eat this right away but it will also be delicious if you need to prepare say a day in advance.