Why does my corn flour dough feel like wet sand?
Corn masa is what you need for this.

The process of nixtamalization makes the corn more easily ground and therefore the texture of doughs made with it will not be "gritty" in the way that a dough made with corn meal or corn flour will be.

Also, corn masa (or masa harina) is more nutritious than standard corn products due to the chemical changes that result from the nixtamalization process.