Prepare a large bowl filled with hot water.
Cut the center cut filet in half, lengthwise, to obtain two 6cm wide logs.
Place each log on a piece of parchment paper.
Baste each log with Oyster sauce and sprinkle the seeds and the salt evenly on all sides.
Place one or two rice galette in the hot water for a few seconds to soften them.
Wrap the log tightly into one or two of the galettes making sure that they overlap and close tightly.
Roll each log wrapped into rice galette into a piece of parchment paper.
Place them side by side in the shallow dish.
Place the dish in the refrigerator for at least one hour, but no more than 2 hours.
Preheat the simmer cabinet between 3 and 4 (80/90°).
Place the dish with the salmon in the cabinet for about 30 to 40 minutes depending o the thickness of the logs.
Check the cooking after 30 minutes. The salmon must not be overcooked! The color should be close to the original color, slightly pinker, and the flesh should flake-out and separate when pressed upon, but in no case, be hard.
Unwrap the salmon when ready.
Serve it warm, accompanied with blinis, potato crepes or toasted Scandinavian black bread and a yogurt/mint sauce