Mix the cassava flour, sea salt, and baking soda together in a medium bowl. Make a well in the center and add the apple cider vinegar, oil, and warm water. Stir to combine; then knead a couple of times in the bowl to form dough.
Divide the dough in half and then each half into 2 -3 balls. (I like to cover the uncooked dough with saran to keep it moist; otherwise, I find it tends to dry out a bit.)
Roll out each ball between two sheets of parchment paper to 1/16 inch, making a 6- to 7-inch circle. I like to use one of my glass storage containers with a 6-inch circumference to cut the shape for tortillas. Add any leftover dough back to another ball and continue in this manner until all dough is used.
Cook each tortilla on a hot griddle or skillet and cook on medium heat 1-2 minutes until bubbles form; flip using a spatula and cook for another minute. Remove and continue with the rest of dough. The tortillas can be made in advance and warmed for a few seconds in the microwave. Store unused portions in the refrigerator for 1-2 days.