According to the racial slur database...
Kimchee - "Kimchee" is a type of ferminted cabbage in Korea, and it sort of sounds like "Korean"
DAK - Dumb Ass Korean. Name given to Koreans by the Whites who visit the country.
Zipperhead - Coined by US soldiers during Korean War. Also used in the film Full Metal Jacket. Two possible reasons: 1) if Asians were shot in the head with high-powered weapons, their heads would split as if you unzipped them or 2) many times the Asians would be run over by military Jeeps, which left tire tracks on them that resembled zippers.
Gook - Term most likely dates back to the Philippine-American War (~1900) and has been used against a wide range of peoples, usually Asians but occasionally Europeans and even the English. Unknown origins, possibly "goo-goo," from the Tagalog language (a major language spoken in the Philippines). Although many have it originating in Korea either by referring Korea's original name, "Hanguk", or during the Korean War when Koreans would ask American GI's "Mi Guk?" ("American?" in Korean) which sounded like they were saying "Me gook." Was soon adopted for use in the Vietnam War.