A derogatory term referring to a Chinese person. The referrence is made because the face is preportionately flat, and thus the Chinese person potentiallypossesses the ability to literaly bite a wall.
"After giving his brother a Morning Wake-up Call, he was completely Wallstered when his brother retaliated by pouring a gallon of sac soup on him while he was tossing the dwarf to some kids program on tv.