Preheat your oven to 350°F.
Combine almond flour, water, ground flaxseed, and fine sea salt in a medium bowl, stirring until a cohesive dough forms.
Lay the dough between two sheets of parchment paper, pressing and rolling it out to about 1/8 in. thickness, aiming for a rough rectangular shape.
Peel away the top parchment layer and, if desired, sprinkle the dough with flaked sea salt, pressing gently to adhere.