I can recommend Peking Eastern House Restaurant at 16041 Frederick Road in Rockville MD (tel 301 527 8558), even if the decor is not so special. Nice lamb dishes.
Does anyone know a restaurant that serves eight treasures rice in the DC area? Grand Sichuan in New York City serves it during Chinese New Year.
Are there any new Uighur or Hui restaurants in DC or New York?
In Los Angeles, I can also highly recommend China Islamic Restaurant at 7727 East Garvey Ave, Rosemead CA (tel 626 288 4246) in suburban L.A. Last week I had their most wonderful lamb dumplings, fresh hand-cut noodles with lamb, sesame bread, and lamb with sa cha sauce...best muslim Chinese food since travelling in Xinjiang, Qinghai and Gansu. And it's not expensive, the restaurant is pleasant, very clean, and well-lit.