The word for foreigner in Korean is 외국인, pronounced something like "waegukin." I hear this word a lot followed by shouts of "Hello!"
Sometimes it's followed by whatever English word(s) the person knows. "Beautiful!" "How are you?" "America!" "I love you!"
By far the best single word greetings I've gotten in Korea have been:
1) From one very shocked middle school boy who did a full stop when he saw me round the corner, jaw dropped to the floor, pointing and shouting,
Because we look so much alike.
2) From an adorable preschooler at the day care center outside my apartment who gave a big toothy grin and excited wave and loudly proclaimed,
"Ni hao ma!"
Because as a foreigner, Chinese is understood by me just as easily as English, right?
Living in a homogeneous foreign country has its moments of utter hilarity.