Add flour and salt to a large mixing bowl, and stir.
Add the coconut oil to the flour and salt mixture, and use a fork or a pastry cutter to combine until small pea-sized lumps appear. Add water and sourdough starter and mix together well, until dough comes together in a ball.
Cover bowl and allow to sit at room temperature for 8-12 hours.
The next day, or when you're ready to make the tortillas, divide the dough into 12 pieces. Form each piece into a ball and put them back into the bowl.
Grease a griddle or large skillet with a bit of oil, and preheat on medium heat.
Lightly flour a clean surface, and roll out a ball of dough as thin as possible (about 1/8"-1/4"" thick).
Put the tortilla onto the hot griddle or skillet, and allow to cook for 2-3 minutes per side. Once it's done on both sides, put it on a plate lined with a clean tea towel, and cover with a second towel to keep warm.
Repeat the above steps with each ball of dough, until all tortillas have been cooked.
Serve immediately, while still warm, or allow to cool and store in an airtight container. May be frozen in a plastic zipper bag to use later.