https://www.tsunagujapan.com/16-top-selling-items-at-lawson-...
It's basically a sandwhich, right? Only that it costs 5-10x more.
One thing I noticed since is that it can be a great vegan option: You can make one from rice salt and dried kelp/seaweed plus some pickles (umeboshi etc.)
Are they hard to make at home? I haven't found great/reliable spots to get these in SF. (Where are the great SF spots for these??)
We love this Nori Komi furikake, you can put it on anything, including buttery popcorn!
https://www.amazon.com/Jfc-International-Seasoning-Furikake-...
My favourite is wasabi tuna in a tube shape.