Add the flaxseeds and salt into a mixing bowl and stir to combine. Add the water and stir once again. Cover the bowl and place it in the refrigerator for 12-18 hours.
After 12 hours, transfer the flaxseed mixture onto a piece of parchment paper. Place another piece of parchment paper on top and roll the "dough" out as evenly as possible. I like the dough to be about two layers of flaxseed thick. If the crackers are too thin, they tend to be quite brittle.
Remove the top layer of parchment paper. Using a knife or a pizza cutter, score the dough into shapes (squares, rectangles, triangles ...). If you roll out the dough too thin, you might find that the flaxseeds adhere to the top layer of parchment paper. If that's the case, just bake the cracker with both pieces of parchment paper. (The only downside is that you won't be able to score the dough before baking).
You can dehydrate or bake the crackers.Dehydrate the crackers at 110°F/45°C for ~ 6 hours, until dry and crispy. Flip the crackers halfway through dehydrating to promote even even browning.
Bake the crackers at 300ºF/150ºC for ~ 40 minutes, until crispy and golden brown. (The time will depend on how thin/thick you roll the dough out). If you find that most of the crackers are cooked through but a few right in the center are a little soft, you can just bake those few again for ~5 minutes until they've dried out more.
Allow to cool for 10 minutes and then break the "cracker" along the scored lines.
Store the crackers in an air-tight container for up to 3 weeks.