In a large mixing bowl, combine ground pork, kimchi, shredded yellow onion, finely chopped garlic, grated fresh ginger, soy sauce, rice wine, egg, sesame oil, salt, and ground black pepper. Mix well until fully combined.

Take a dumpling wrapper and place about 1 tablespoon of the filling in the center. Moisten the edges with water, fold in half, and pleat to seal.

Heat 1 tablespoon of vegetable oil in a skillet over medium heat. Add the dumplings and cook until the bottoms are golden brown, about 3-4 minutes.

Carefully add cold water to the pan (enough to cover the bottom) and cover with a lid. Steam the dumplings for about 8-10 minutes until cooked through.

Remove the lid and continue cooking until the water has evaporated. Add the remaining tablespoon of oil to crisp the bottoms if desired.

Transfer dumplings to a serving platter and sprinkle with black sesame seeds and finely chopped green onions.