I am a CFI in Korea, and I have FAA CPL. Can I log my logbook as instructor time? (FAR 61.41)
You can log what ever you want in your own logbook. However, since you did not receive your CFI by meeting the requirements of U.S. FAR Part 61 you are not an "Authorized Instructor" (FAA Definition of Authorized Instructor)
So, any FAR that requires instruction be given by an Authorized Instructor would not apply to you and could not be counted toward meeting any regulatory requirements.
FAR 61.41 relates to instruction by non-FAA certificated Flight Instructors (see FAR 61.41) and does not seem to apply to your question since you are asking about non-military instruction in the U.S.