Line a bench with plastic wrap and lay out 3 of the nori sheets on top. Use a pastry brush and brush each sheet with the sugar syrup. Place another nori sheet on top of each of the first 3 and repeat the process with the sugar syrup. Repeat with the remaining nori to make 3 stacks of 4 layers. Place the nori stacks on a dehydrator tray in a food dehydrator and dehydrate at 55°C (130°F) for 24 hours until very crisp.
Break up the dried nori sheets and place in a spice grinder. Grind to a fine powder, and then sift through a sieve into an airtight container and store until required.
To make the nori salt, grind the dried nori sheets with