It has the scientific name of Capsicum annuum, and is a sweet pepper—though apparently one out of every 10 is supposed to be spicy, which is a fact that baffles me. According to Wikipedia, that spiciness can be caused by such factors as how much sun it gets, then again, so many chili peppers are affected in the very same manner. Nothing new there, but the Shishitō is, generally-speaking, a sweet chilli pepper that looks like the Spanish Padrón pepper, is you are the type of person who knows their peppers. I don't.
As you can see from the image above, it is a small, slender finger-long pepper with thin walls (I know you can't tell how thin the walls of the pepper are!).
Back to the sweetness versus spiciness, it is a green pepper that will turn red when ripening, BUT, the pepper is usually plucked from the vine when still green. That's why it hasn't, usually, gone all hot.
The name of the pepper is interesting.
Because to some people the tip of the pepper known as the tōgarashi (唐辛子) looks kind of like the head of a lion, it has the lion word "shishi" (獅子) as part of its overall moniker: 獅子唐辛子, which is, as mentioned above Shishitō garashi. I don't see that whole 'lion's head' thing, but whatever.
For cooking, a hole is poked in the pepper beforehand to keep expanding hot air from bursting the pepper.
It may be skewered then broiled (grilled), or pan-fried in oil, or stewed in a soy sauce and dashi-based liquid. It is thin-skinned and will blister and char easily compared with thicker skinned varieties.
The peppers have a smoky flavor, a touch of sweetness, with a silky texture, which is too much information for a guy who would probably just pop a few into his mouth and chug a beer. As well, having a stomach that doesn't digest green peppers (and cabbage, cauliflower, lettuce and broccoli well - I can get gassy... though I do eat all of the above - except green bell peppers which are usually bitter) I wonder how my stomach would react. Probably no big deal. Cauliflower and lettuce are two things I eat several times a week.
Ways to cook the peppers include lightly oiling them, then grilling or pan frying in a wok or skillet in olive oil until blistered.
From there, some people like to add a squeeze of lemon or splash of ponzu and some high quality sea salt.
Some other popular accompaniments are: miso vinaigrette, yuzu-flavored salt and bonito (type of fish), sesame oil and dash of ponzu sauce, and garlic scallion sauce. And don’t forget that these peppers are an ideal choice for tempura.
It is also currently all the rage here in Canada for chefs, who are using it with regular... uh, regularity. Writing words is tough.
In Japan, you can go visit an izakaya - a place where you can go and have a few drinks, sitting on a tatami mats with a low table, being served tsukidashi or otoshi (both are appetizers or snack foods). I suppose if you were in Spain it would be called tappas.
Anyhow, some izakaya do serve cooked up Shishitō peppers.
If you see it in the grocery store or farmer's market, why not give it a try?
Andrew (not a shill for the Japanese peppers market) Joseph