How to Make It
Heat a large cast-iron skillet over medium-high. Add chiles; cook, stirring constantly, until slightly toasted, about 15 seconds. Transfer to a large plate. Add cacao nibs to skillet; cook, stirring often, until darkened and fragrant, about 1 minute. Transfer to plate with chiles; sprinkle with salt and, if desired, smoked Pimentón. Let cool 20 minutes. Working in 3 batches, process chile mixture in a spice grinder until finely ground, about 10 seconds. (Do not over-process or the cacao will start to melt and become sticky.) Transfer to an airtight container, and store in a cool place up to 2 months.