Rinse the rice under cool water until the water runs mostly clear. Add it to a saucepan with the water and ½ teaspoon of the sesame oil. Bring to a boil, cover, and reduce the heat to low. Cook until the water is absorbed and the rice is tender, then let it stand covered while you prepare the rest of the meal.

Preheat a smoker to 250°F. In a large bowl, combine the ground beef, ground pork, panko, egg, 1 tablespoon of the soy sauce, ½ tablespoon of the gochujang, 1 teaspoon of the ginger, half of the minced garlic, and the black pepper. Mix gently until combined, then shape into a compact loaf.

Place the meatloaf on a smoker-safe tray and smoke until its center reaches 160°F, checking with an instant-read thermometer. Let it rest for 10 minutes before slicing.

While the meatloaf smokes, warm the remaining sesame oil in a large skillet over medium-low heat. Add the sliced onions and cook, stirring often, until very soft and deeply golden, about 25 to 30 minutes. Lower the heat if they start to brown too quickly.

Stir the brown sugar, rice vinegar, remaining tablespoon of soy sauce, remaining ½ tablespoon of gochujang, remaining teaspoon of ginger, and remaining garlic into the onions. Cook for 2 to 3 minutes, stirring until the onions are glossy and the sauce coats them.

Fluff the rice with a fork and stir in the sesame seeds. Divide the rice among four bowls. Add sliced meatloaf and spoon the gochujang onions over the top. Finish with the sliced green onions.