Ever heard of friarielli? According to a recent Chowhound discussion, they're the Italian version of Japanese shishito peppers. They can be hard to find, but when nomadchowwoman found some recently, she grilled them whole, then sprinkled on feta and dipped them in aioli, a fabulous combination. Unadorned, friarielli have a fruity flavor with mild but varying heat.
Novelli says you can always use shishitos if you can't find friarielli. Look for shishitos at Japanese or Korean markets (the latter often label shishitos "Japanese peppers," says chefj). And padrón peppers are essentially the Spanish version of friarielli, Novelli says.
Photo of fried padrón peppers from Shutterstock