Place cod on a shallow bowl. Sprinkle salt, pepper, and ginger all over the cod. Place sliced kimchi on the top.
Fill a large pot with about an inch of water. Place in a metal rack or stand in the middle of the pot. Bring the water to a boil. Place the dish with the fish on the metal rack then place lid on the pot. Reduce heat to medium and allow fish to steam for 12 to 15 minutes. When cod is done, it should flake easily.
Place minced garlic and vegetable oil in a small microwave safe bowl. Microwave on high for 1 minute 30 seconds. Remove and mix in soy sauce. Set aside.
Remove fish from the pot and drain off some of the liquid. Drizzle garlic oil over the fish. Garnish with sliced green onions.