Preheat oven to 300º F.
Combine seeds and sea salt in a bowl, and stir to mix them together.
Add water, and allow the seeds to soak for 5-10 minutes. The chia seeds absorb the water and become sticky, holding the seeds together in a “dough”.
Add the cracker dough between a large folded sheet of parchment. Use a rolling pin to roll it out as thin as possible. A 14″ x 12″ rectangle will ensure these crackers are nice and thin, allowing them to crisp up while baking. Cut off the top layer of parchment paper, and slide the crackers carefully onto a 1/2 sheet baking tray.
Bake the crackers for 30 minutes. At this time, the crackers should have started to brown around the edges but still be soft in the center (they will have dehydrated enough that you can pick up the whole sheet of crackers without it breaking).
Flip the large sheet of crackers over, and continue baking for 20 more minutes. Allow heat to escape the oven, and leave the oven door cracked, while the crackers remain in the oven for about 20 minutes to slowly cool. This allows them to get as crisp as possible. Be sure to check crackers to make sure they aren’t over browning (oven temperatures vary, so yours might cook them faster!).
Break the crackers into smaller pieces for serving and storing.