Preheat oven to 450. Place the salmon on a rimmed baking sheet, tucking the narrow ends underneath as needed to make the filet the same thickness all around. Roast for 15 minutes.
Meanwhile, make the sauce: melt the butter over medium heat. Whisk in the flour and stir for one minute.
Pour in the wine and simmer for 10 minutes. Season to taste with salt and pepper.
Using two forks, carefully pull the salmon into large chunks. Spoon a little sauce on to each plate, place a few salmon chunks on top, drizzle with more sauce and scatter some capers on top. Serve at once.