These are Friariello Barese peppers from Lagier Ranches
at our local farmers market in Oakland, CA. They aren't the exact variety you'll find in Spain and Portugal, but are an Italian variety that is close enough. More on these peppers from Vegetables of Interest
Unlike true Padron peppers, apparently none of these will be hot. Part of the fun of Pimientos de Padrón is coming across a hot one, but these will still taste great.
Wash and dry the peppers.