In a large bowl, mix the beef or pork, ginger, garlic, gochuang, sesame oil, sugar, soy sauce and black pepper. Cover and marinate, in the refrigerator, at least 2 hours and preferably overnight.
Heat a large heavy-bottomed pan or cast-iron skillet over high heat with the vegetable oil. When shimmering hot, saute the diced onions for about 4 minutes, stirring constantly, or until soft. Add the marinated meat and saute, stirring, just until fully cooked through, 5 to 7 minutes. Drain any residual fat, if needed.
While the meat cooks, toast the buns.
Divide the meat and place it into the buns. Serve, ideally with pickles and shredded iceberg lettuce.
Quick Kimchi Persian Cucumbers:
Yield:3 1/2 to 4 cups
Make the cure mix: In a small bowl, stir together the salt and 1 1/2 teaspoons of the sugar.
Make the kimchi marinade: Add the pear, gochugaru, fish sauce, garlic, ginger and remaining 2 tablespoons sugar to a blender and blend until smooth.
In a large pickling jar or lidded container, combine the cucumber and the cure mix; let sit for 15 minutes. Drain excess liquid, then add 1 cup of the kimchi marinade, stirring to coat. Refrigerate for at least 2 hours. This kimchi will keep up to 1 week in the refrigerator.