Rinse the seaweeds several times to remove the salt. Cut into desired bite size length.
Heat the sesame oil gently in a pot over medium heat and add the beef, saute until no longer in pick. Add the seaweeds to the beef and cook for another 1 minute. Add the water and bring the whole thing to boil. Cover with a lid and simmer the soup over low heat for 15-20 minutes until the seaweeds get soft.
Add garlic and the Korean soy sauce for soup. Season with more soy sauce or salt according to your taste. Serve warm with rice and kimchi.