Preheat a large cast iron skillet over high heat. Once the skillet is hot, add the shishito peppers directly to the dry pan. Cook them for 6 to 8 minutes, tossing occasionally, until they become tender and develop deep blistered spots. Ensure the peppers remain in a single layer so that they make consistent contact with the heated surface for even charring.
Once the peppers are evenly blistered, drizzle with toasted sesame oil, allowing the rich, nutty aroma to coat them. Sprinkle with sea salt to enhance their natural flavors, followed by a scattering of sesame seeds for added texture.
Serve the blistered shishito peppers immediately, accompanied by small bowls of tamari and creamy peanut sauce for dipping. Enjoy them hot for the best flavor and texture.