In Iceland’s Westfjords, hundreds of kilos of white gold are produced every day simply using the region’s unique characteristics. Made with geothermal energy, Saltverk’s flaky, crunchy sea salt is not only Noma’s salt of choice, it’s also carbon neutral. We travel to this remote locale to learn how founder Björn Steinar Jónsson is turning seawater into a coveted ingredient at the world’s finest restaurants