Add the gosari. Boil over medium heat, covered, until tender. The time can vary depending on the gosari. Turn the heat off and let it cool in the cooking water.
Sauté in a skillet with vegetable/canola oil. Cook for a few more minutes, stirring occasionally, until the liquid is almost gone. Add the scallion, sesame oil, and sesame seeds. Stir well before turning the heat off.