Heat a large non-stick skillet over medium-high heat with half of the toasted sesame oil.
Add the diced chicken breast, seasoning with sea salt and black pepper; cook until golden and cooked through, then remove and set aside.
In the same pan, add the remaining sesame oil, minced garlic, and the white parts of the green onions, sautéing until fragrant.
Stir in the chopped kimchi and gochujang, cooking for 2 minutes until the kimchi begins to caramelize slightly.
Add the cooked brown rice and tamari to the pan, breaking up any clumps and tossing until the rice is well-coated and heated through.
Return the chicken to the pan, mix well to combine, and transfer the rice mixture to a serving bowl.
Wipe the skillet clean, spray with a light coating of oil, and fry the egg until the white is set but the yolk remains runny.
Top the bowl with the fried egg and the remaining sliced green onion tops before serving.