Line a baking sheet with a nonstick liner.
Melt the chocolate in a large, heatproof bowl set over simmering water, stirring until the chocolate is melted and smooth, about 4 minutes. Remove the bowl from the heat and add the popcorn, peanuts, and salt. Fold the mixture until the popcorn and peanuts are evenly coated with the chocolate.
Scrape the mixture onto the prepared baking sheet and spread into a thin layer. Refrigerate for about 30 minutes, or until cold and firm. Break into small clusters and store in an airtight container in the refrigerator for up to 5 days.