Heat a large cast iron skillet to high heat. Add the peppers to the dry skillet and cook, tossing occasionally, until tender and blistering, about 6 to 8 minutes. As you work, try to keep the peppers in a single layer so that they make consistent contact with the hot pan.

Drizzle the peppers with sesame oil, and sprinkle with sea salt and sesame seeds. Serve with tamari and peanut sauce, for dipping.