Preheat oven to 350°F and line two baking sheets with parchment paper.
In a large bowl, stir together the flour, starch (for the crisper cookie), coconut flakes (for the chewier cookie) baking powder, baking soda, and salt.
In a medium bowl, combine the flax egg, lemon juice, lemon zest, coconut oil, sugar, vanilla (for the chewier cookie) and water.
Add the wet ingredients to the dry and mix thoroughly.
Scoop the dough onto the cookie sheets using a small cookie scoop. If making the chewier cookies, flatten the dough lightly.
Bake for 15 minutes, switching and rotating the baking sheets, if needed, for even baking.
Cool on a wire rack and store in an airtight container.