To a large ddukbaeggi (clay Korean pot) or medium Dutch oven over medium heat, add sesame oil (or vegetable broth) and gochugaru. Cook for about 1 minute until gochugaru starts to froth. Add shiitake mushrooms and stir until they are coated with oil and gochugaru. Cook for about 2 minutes, until mushrooms start to brown.
Add diced onion, scallion whites, and garlic until garlic softens and onions begin to throw translucent (about 2 minutes). Make sure to stir regularly, so that the gochugaru doesn't burn.
Next, add your potatoes, kimchi, gochugaru, and gochujang. Stir all the contents of the pot together until they are all evenly coated. Deglaze your pot with kimchi liquid and soy sauce, stirring so that everything is well-incorporated. Add cracked black pepper. Then, add your vegetable broth (or water). Drop in the dashima and increase the heat to a medium-high until the pot comes to a boil. Then reduce heat to low and allow the pot to simmer for about 10 minutes, until potatoes are almost cooked.
Add your sliced tofu, black beans, and enoki mushrooms. Cook for an additional 3 minutes, until potatoes are fully cooked. Garnish with scallion greens, an extra drizzle of sesame oil (optional), and remove from heat. Serve with bowl of rice.