This
Washington Post dining guide might help you. Refine your search by selecting the Chinatown area and price range. You can view results on a map, and sort the list by distance, name, or editor's picks. I've had to stay in the convention center area occasionally for work, and it's not as restaurant-rich as other parts of DC, but it looks like there are some suitable options for you: 701, Cafe Atlantico, Clyde's at Gallery Place, Hill Country, Jaleo, Oya, Proof, The Source, Zaytinya, Acadiana, Asia Nine ... ? Next time I go to DC I want to try Acadiana.
Good luck.
"Your swimming suit matches your eyes, you hold your nose before diving, loving you has made me bananas!"