Set oven temperature to its lowest setting (ours was at 170F). Use convection function if available.
Combine the sea salt, zest and juice, stirring until slushy.
Spread the salt mixture evenly on a parchment lined baking tray, or on a glass baking dish.
Place tray in the warm oven and leave the door ajar (you can prop a wooden spoon to leave a small gap). Dehydrate the salt for 1 ½ to two hrs, stirring every 3 minutes using a wooden spoon to break up the clumps.