Light a grill or preheat a grill pan. Cut a cross pattern into the ends of each hot dog. Grill over moderately high heat until lightly charred all over, about 4 minutes. Place a hot dog in each bun and top each with 1 teaspoon of the remaining wasabi mayonnaise. Spoon about 1 cup of slaw onto each hot dog, sprinkle with the sesame seeds and serve.