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.