Double-skin, or Liang Zhang Pi, is made from Mung Bean noodle sheets, a specialty of Shandong cuisine and a dead giveaway that it is a Korean-Chinese style restaurant run by Chinese of Shandong descent.
Great China is known for its Peking Duck dish (though not a Korean-Chinese specialty). One of the few and best places around bay area for it. Another nice item is the Crab meat and egg dish in lettuce cup (sorry, don’t remember the exact name). Generous portions of hand pulled crab meat and egg whites lightly stirred together creates a marvelous flavor. These are probably the best dishes there. I would not even endorse their noodle dishes even though it is a specialty of Korean-Chinese genre. Their versions are not that well done.
For more information on what Korean-Chinese is, please see here.