Transfer the frozen corn to a deep bowl, pour boiling water over it and leave for 7 minutes. (or use canned corn, drained)
Drain all the liquid from the corn and transfer it to another deep bowl. Add chopped red onion and garlic. Remove the skin from the roasted poblano and chop it finely. Add peppers, salt, chopped cilantro, and lime juice into the bowl.
Finally mix everything, cover the bowl with cling film. Put in the refrigerator for half an hour or longer and then serve.