Cook the shishitos peppers. Heat 1 Tbsp grape seed and 1 tsp sesame oil over high heat in a large cast iron or heavy bottom skillet until very hot, but not smoking. Add shishito peppers and cook, stirring often, until blistered on all sides. This can take 5-10 minutes depending on how hot your pan is. You're looking for the peppers to be tender, but not mushy.
Toss with sauce. When the peppers are almost there, add garlic, 1 Tbsp soy sauce, and 1 tsp sesame seeds. Cook until garlic is fragrant, about 30 seconds then remove from heat. Sprinkle with 1 tsp Kosher salt, then serve immediately with additional soy sauce for dipping.
