Gravlax is an ancient means of preserving fish. While traditional methods take several days to cure, this recipe is much quicker but yields a really fantastic result. Placing the salmon in a vacuum-sealed bag with a salty, citrusy brine ensures a fast and even transfer of flavor and salt throughout the fillet. To serve, simply rinse off the brine, roll in finely chopped dill, slice thin, and drizzle with olive oil.