Pat the cod fillets dry with a paper towel and season both sides with sea salt and black pepper.
Heat avocado oil in a large non-stick skillet over medium-high heat.
Place the cod in the skillet and sear for 3 to 4 minutes per side until golden and the fish flakes easily.
Remove the cod from the pan and set aside on a plate.
In the same skillet, add the toasted sesame oil, minced garlic, and grated ginger, sautéing for 30 seconds until fragrant.
Add the chopped kimchi and cooked brown rice to the skillet, stirring constantly for 2 minutes to incorporate the flavors.
Push the rice mixture to one side of the pan and crack the egg into the open space, scrambling it until fully cooked.
Fold the scrambled egg, tamari, and sliced green onions into the rice mixture.
Divide the kimchi fried rice between plates and top with the pan-seared cod fillets.