DC has many ethnic neighborhoods with great restaurants. So check with your hotel concierge, check the local papers and magazines, even the yellow pages in the phone book.
If you want a real Asian experience, head out Rockville Pike (Wisconsin Ave) beyond White Flint Mall to Joe's Noodle House. It's like a back street family restaurant in Beijing. You may be the only Euro there. The fresh daily items are listed on the board behind the counter and the hostess does speak English and can help you with the menu which is mostly in Chinese.