Add oil to a skillet over medium heat and let it heat up. Stir fry the pork and potatoes together, stirring it for about three minutes or until slightly browned.
Add the zucchini and onions, sautéing all ingredients for another three minutes.
Put the bean paste, sugar, sesame oil, and garlic, again continuing to stir until all ingredients are well combined. Continue to sauté everything for about four minutes.
Add the lukewarm water and carrots. Increase the heat and bring to a boil. Once it begins to boil, reduce the heat and let it simmer.
While it simmers, mix the cornstarch with cold water, then add it to the sauce. Stir the mixture until it thickens.
Continue to cook for about 15 minutes. Remove from heat when the vegetables and meat are tender.
While the sauce and vegetables are cooking, cook noodles in a large pot of water according to package directions.
Once the sauce and noodles are ready, put the noodles in a large bowl, then add the chunjang sauce over it. Sauce noodles, mixing everything together.
Serve the noodles with sliced raw onions, cilantro julienned cucumbers and a splash of white or rice wine vinegar.