In a large bowl, add the corn masa and the salt and mix well.
Add the hot water, and mix into a soft dough (it should be about as firm as cookie dough).
Add more water if needed.
Line a tortilla press with a zip lock bag (I just cut down the sides)
Divide the dough into roughly 20 dough balls
Place 1 ball onto the lined tortilla press and .... press.
Carefully remove the tortilla from the press, and add to a medium hot cast iron skillet.
Let the tortilla cook about 30 seconds, until the edges look like they're drying... then flip
Cook a further 45-60 seconds, then flip again - the tortilla will puff up.
Add tortilla to a towel line tortilla warmer.
Repeat with remaining dough balls.
Notes
Are corn tortillas gluten free? Yes! As long as you check the product you use - the masa harina is gluten free (as is water and salt)
How to make corn tortillas without a press? Just grab a rolling pin, and roll out to a very thin, even circle. It will take longer, but homemade tortillas are so worth it!
How to keep homemade corn tortillas soft - humidity is your friend! Using a tortilla warmer is a good option, but wrapping in a clean towel will also do the same job. If you make them ahead, just heat in the microwave wrapped in a paper towel.
Keep the dough covered while cooking the tortillas.
If the dough gets dry, add some more water. Too wet? Add a little more masa.
Flip the tortillas when you start seeing brown spots.