Sourcing & Selecting
Korean grocery market
It is difficult to find noodles that taste exactly like ones served at Korean Chinese Restaurants in Korea. But, you can find similar noodles in frozen format. Usually it's usually labeled as Udon-Jjajang (우동 짜장) noodles or JungWhaMyeon (중화면). I've seen it labeled as "Oriental or Korean Style Vermicelli" in English (although this is a very broad and inaccurate term).
Local Korean grocery market
You can buy Korean noodle online here.