Pre-cook the oven at 350º.
In a bowl (or right in your pie plate!), combine the rice flour, almond flour, tapioca starch and ground chia seeds. Use a fork to ensure there are no chia seed clumps anymore.
Then, distribute the coconut oil all over the flour in small clumps (do not transfer the whole ⅓ cup of oil all in the same spot!) and, still using your fork, mash the oil to break the clumps in smaller pieces and slowly incorporate the flour within the oil. Keep mashing until you reach a crumbly texture.
Add the cold water over the mixture and keep mashing with your fork. I usually need 5 tablespoons of water, but you can start with 4 and add 1-2 more tablespoon as needed. The dough will slowly start to come together as you are mashing. It is ready when there are no dusty fine flour left at the bottom of your dish.
Once the dough looks ready, then set your fork aside and use your fingers to press on the dough and shape your pie crust. Do not leave any cracks behind and shape the sides as well so the crust is tight and uniform.
Poke the bottom of the crust with a fork and pre-bake for 10-17 minutes. Then, use as directed by your recipe.