I acquired some Shishito seeds from some fresh fruit I purchased near Dallas, TX last year.
Despite numerous attempts, I have not yet been able to get any of those seeds to germinate.
I think the chiles where probably a bit on the immature side (typical of fresh produce), so the seeds may not be particuarly viable.
Agree with the others though... no real piquance... more of a sweet pepper... and I think "Shishito" roughly translates from Japanese to something akin to "Lion's Face" due to the unique shape of the pod.