Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.
Mix almond flour, walnuts, flax seed meal, and salt together in a bowl until well combined. Add water and olive oil; mix until dough is moist and holds together.
Turn dough onto prepared baking sheet. Place a second piece of parchment over dough. Roll dough, using a rolling pin, into a 1/16-inch thick rectangle. Remove top piece of parchment paper and cut sides of dough to make an even rectangle. Add excess dough to corners or 1 end of rectangle and re-roll to uniform thickness.
Cut dough into 1-inch squares using a pizza cutter, keeping dough still attached.
Bake in the preheated oven until outside edges of dough are browned, about 15 minutes. Cool crackers on the baking sheet; break into squares.