Preheat the oven to 350 degrees F and line a baking sheet with parchment paper.
To make the flax egg, combine one tablespoon flaxseed meal and 3 tablespoons water, and allow to sit until ready to use.
In a small bowl, combine the oat flour, rolled oats, baking soda, and salt.
In a bigger bowl, whisk together the coconut sugar, melted coconut oil, tahini, flax egg, and vanilla.
Fold the dry ingredients into the wet ingredients. Then, fold in the chocolate chips.
Scoop two tablespoon sized balls and place two inches apart on the baking sheet. Flatten each ball of dough out slightly and top with additional chocolate chips, if desired.
Bake the cookies for 8-10 minutes. Top with flaky sea salt and enjoy!