Whisk tapioca flour and flax seed together in a bowl. Quickly stir egg and olive oil into tapioca flour mixture; add enough water to make dough stick together. Turn dough onto a work surface and roll to about 1/8-inch thickness. Cut dough into preferred size.
Heat coconut oil in a skillet over medium heat. Fry dough, working in batches if needed, in the hot oil until crackers are lightly browned, 2 to 3 minutes per side.
