This recipe makes enough sauce for two servings but just enough noodles for one so that you can save the remaining sauce for another day. Double the noodles if you’d like to share this dish or eat an extra-large portion on your own. You can find chunjang, sometimes labeled fermented black bean paste or simply black bean paste, online and in Korean markets. The same is true of the noodles, but you can substitute spaghetti or linguine as well.
Heat the grape seed oil in a wok or large skillet over medium-high heat. Add the pork and potato and cook, stirring occasionally, until the pork is golden brown and crisp, 4 to 5 minutes.
Add the onion and zucchini and cook, stirring, until the onion starts to look translucent, 3 to 4 minutes. Add the black bean sauce and cook, stirring, for 1 minute. Stir in 2 cups water, raise the heat to high and bring to a boil. Cover partially with a lid, reduce the heat to medium-low and simmer until the pork and potato are cooked through, about 10 minutes.
Meanwhile, cook the noodles according to the package’s directions.
Uncover and smash a few potatoes into the sauce to thicken it. Add the sugar and sesame oil and stir well. Transfer the noodles to a serving dish and top with the sauce and cucumber.