Mix all the marinade ingredients together and add in the steak. Marinate at least one hour and up to overnight.
Cook the steak on a grill and cook to medium-rare.
To make the rice add the oil to a skillet over medium-high heat. Add in the onion and cook for 3-4 minutes.
Add in the garlic and cook for one minute.
Stir in the Gochujang and the Kimchi, stir until heated through.
Add in the rice, soy sauce and sesame oil.
Cook, stirring often, until well combined and heated through.
Thinly slice the steak and add into the rice. Optionally, you can chop the steak into smaller pieces to mix into the rice.
Top with sesame seeds and green onions and serve with extra kimchi.