Blend the white wine, mirin, soy sauce, garlic, and ginger in a blender. Place the salmon in a dish with a lid. Pour the marinade across the top. Let it rest in this marinade for at least 10 minutes while the collards are prepared, up to 24 hours of marinating.
Bring a pot of water to a boil. Season generously with the salt. Dip the collard greens into the water for about 10 seconds, use tongs or simply your finger to hold the stem end while the leaves get a quick bath. Remove each leaf and place on a wire baking rack to cool. Imagine you are wrapping a present and cut the salmon into pieces that will fit nicely inside the wrapped leaves.
Pour the marinade off of the salmon into a saute pan with a lid. Bring up to a simmer over high heat. Reduce the heat slightly to medium as soon as it boils up. Cover with a lid once it is simmering.
Trim the stems of the greens. Arrange the slices of carrots in the middle and place the salmon on top, flesh side down. Wrap the salmon with the green, by folding over any slightly torn pieces, tucking them under and then finishing it with a pretty part of the leaf.
Place the salmon in the simmering marinade, seem side down. Cover with the lid and check after just five minutes. It will feel barely firm to the touch when it is done. It may need another minute or two, but watch it closely and don’t let it firm up too much. Remove the salmon and place on a cutting board with the lid on top. Since they are little bundles of heat, the hot outside will continue to heat into the center. If you prefer a more rare salmon, cook it only for 2-3 minutes.
Once the salmon is removed, blast the heat on the marinade to a high boil. Stir periodically, until it is syrupy thick and reduced in half.
Place the salmon fillets on a dish and drizzle the sauce on top.