Preheat oven to 200°C (or air fryer to 180°C).
Wash and boil potatoes in salted water until fork-tender, about 10 minutes. Drain well.
Toss potatoes with melted vegan butter, garlic powder, gochugaru, and salt.
Place potatoes on a baking sheet and gently smash them.
Bake for 20 minutes, or until golden and crispy (air fry for the same time).
While potatoes cook, mix shallots with lime juice in a bowl. Add vegan mayo, gochujang paste, vegan fish sauce, coriander, and chives.
Drizzle half of the dressing over the crispy potatoes while hot.
Finish with remaining dressing, herbs, and black sesame seeds before serving.