In a medium bowl, mix the masa harina and salt. Add the lime juice and ½ c of water. Mix until incorperaated. ontinue adding water, a little at a time, until the masa is just moistened and the dough is holding together. Shape the dough into a smooth ball, cover it, and let it rest for 15-30 minutes.
After the dough has rested, it should feel slightly moist, but not be sticky or tacky at all, kind of like a modeling clay. If it is sticky and too moist, mix in more masa. If it is dry and not holding together in a smooth ball, add a touch more water, until it does.)
Once you dough is a good consistency, divide the dough into two roughly even portions. Shape each section into a ball and press it to flatten slightly. Divide each round into 6, roughly even, pieces. (Creating 12 pieces total.) Roll each piece of dough into a ball about the size of a golf ball. Cover the dough with a damp tea towel while you work on each tortilla.
Preheat a cast iron skillet over medium heat. Cut both sides of a plastic freezer bag (forming a hinge) to fit the shape of your tortilla press (or roughly 7-8 inches if you are not using a press).
Take one ball of dough and place it between the two pieces of plastic. If using a tortilla press, press the dough flat. If flattening by hand, roll or press the dough to about ⅛ inch thickness.
Gently peel the top piece of plastic from the dough. Flip the tortilla into your hand and very gently peel the plastic from the second side.
Place the tortilla into the dry, hot skillet for 30-45 seconds. Flip the tortilla and cook for 30 seconds to 1 min on the second side.
Remove the tortilla and wrap it in a damp tea towel to keep it moist and warm while you repeat the process with the remaining dough.
Tortillas are best if eaten immediately. They can be stored in an air-tight container, on the counter, for up to 2 days.