Heat oil in a wok over medium heat. Add garlic, carrot, and potato. Stir and add salt and pepper. Cook until softened, 5 to 7 minutes. Add zucchini and onion; stir.
Combine cornstarch and water together in a bowl until fully mixed.
Add water, black bean paste, and sugar to the wok and stir. Add starch mixture to wok slowly while stirring; cook until sauce thickens, 3 to 5 minutes.
Bring a large pot of lightly salted water to a boil. Cook noodles in boiling water, stirring occasionally, until noodles are tender yet firm to the bite, about 3 minutes. Drain.
Serve noodles in a large pasta bowl and add black bean mixture on top. Mix well.