In a bowl, mix well canned tuna with mayonnaise and salt, set aside.
Sautee diced carrot over medium heat for about 3 minutes. Transfer the carrot to a mixing bowl.
Add cooked rice, sesame oil, crushed seaweed, and sesame seeds to a mixing bowl then mix until well combined.
Take about 2 tbsp of rice mixture then flatten it on your hand, place about ½-1 tbsp of tuna filling or ground beef bulgogi then carefully wrap until the filling is fully covered and shape the rice into a ball. Korean rice balls are ready to serve, enjoy!