Tip : The length of time to cook the cod depends on how thick the cod is. If you buy cod that is 1" thick, you will need to cook for 4-5 minutes per side, if you buy filets then it may be better to cook for 3 minutes per side.
Pour marinade ingredients into a resealable plastic bag, add 2 slices of 1" thick cod or halibut, and make sure that the fish is completely covered. Refrigerate for an hour before cooking.
Pickled Cucumber
Using a potato peeler or a mandolin, cut thin ribbons of 1 whole Persian cucumber onto a plate. Spread out so they don't overlap and drizzle with 2 tbsp Marukan seasoned rice wine vinegar. Turn to make sure that both sides are covered in the vinegar. Set aside until ready to assemble sandwich.
Searing the Fish
Remove fish from marinade and set on a paper towel. Blot the fish to remove most of the marinade.
Transfer remaining marinade into a small saucepan. Bring to a boil over medium high heat, then reduce and simmer, about 5 minutes. Remove and set aside until ready to use.
Spray a medium skillet with vegetable spray and heat over medium high heat for a couple of minutes.
Add marinated fish filets to the skillet and sear over medium high heat for 4-5 minutes or until the filets are golden brown. Turn and sear the second side for another 4-5 minutes, or until the fish flakes easily.
Asian Slaw
Combine 1/2 bag Asian Slaw Mix, 1 whole green onion, sliced, 2-3 sprigs fresh cilantro leaves and 2 tbsp Kewpie mayonnaise. Toss to combine.
Assembly
Cut buns in half and toast for 1-2 minutes under a pre heated broiler.
Cover the bottom half of the bun with Asian slaw and top the slaw with the seared fish filets. Drizzle with the thickened reserved marinade.
Top the fish with a couple of slices of pickled cucumber. Place to bun on top and serve.