You have to edit file 'public/tools/access.php' and add 'translate.php' to the list of files. Then browse to 'http://<opengoo>/public/tools/translate.php' and follow instructions. When you finish translating you can download a zip file from that same page that you can send to us.
Another way would be to create a copy of the folder 'language/en_us' that you should name after the korean locale "ko_kr" and then manually translate all strings after "=>" or ":" with a text editor.