Pimientos de Padron equivalent In Spain I had a wonderful tapa called Pimiento de Padron. Green chiles fried in olive oil and salted. What type of chile could I find in the US to replicate this dish? The chiles should be mild, with the odd spicy one.
Russian roulette peppers!

Not sure if there is a good substitute you can buy already grown?

If you live near a warm coast try growing your own. Good seed suppliers (Johnnyseeds, LocalHarvest etc - Peperone Padron in NZ from italianseedspronto) should be able to help, or check Ebay or Amazon