Heat 1 tablespoon of oil on medium-high heat in a large skillet or wok. Add the onion and cook until it starts to brown, about 5 minutes. Stir occasionally.
Add the kimchi and cook until it isn’t too juicy anymore and is heated through, about 5 minutes. Add the green peas and cook until bright green and heated through, about 3 minutes. Set aside.
Break the rice apart with a spoon to remove clumps. In another skillet, heat the remaining 1 tablespoon of oil on medium-high heat. Add the rice to the oil and cook until heated through and crisp, about 3 minutes.
Add the tamari and kimchi brine, and cook until absorbed and fragrant, about 2 minutes. Be sure to stir occasionally.
Stir the rice into the vegetables to combine. Cook for another 2 minutes to let the flavors meld. Serve with your garnishes of choice.