1. Preheat oven to 400 degrees F. Wash the fish well and pat dry with paper towels. Stuff the cavity with the thick slices of ginger and garlic. Rub the outside of the entire fish with vegetable oil.
2. In a medium bowl, mix together the salt and egg white. Add a dash of water until the mixture becomes pasty like sand and sticks together.
3. On a baking sheet, spread out a layer of salt approximately the size of the fish about a quarter of an inch thick. Place the fish on top, and scoop the rest of the salt over and around the fish. Make a ¼ inch thick “shell” around the fish, creating a tight seal, leaving the tail and the head exposed.
4. Place in oven and bake for about 30 – 40 mins, and let rest for 10 mins. Use a thermometer to check the internal temperature, should read about 145 degrees F.
5. Meanwhile, make the soy ginger sauce. In a small bowl whisk together the soy sauce, mirin, sugar, ginger, sesame seeds, garlic and chili flakes. Set aside.
6. When the fish is done. Crack open the crust, and remove the fish, and serve immediately with soy ginger sauce on the side or drizzled on top.