JjajangMyun at Choon Hwa Won near DC

Let me make your life easy and tell you what you need to order when you come here: 

짜장면 (Jjajangmyun): black bean Korean-Chinese noodles.
탕수육 (Tansuyuk): Crispy sweet and sour pork  

aka the food you always see people ordering in Korean Dramas.