Cut from a freezer bag 2 circles of plastic, the width of your tortilla press.
Mix the masa harina and warm water until a dough is formed.
Knead dough for about 2 minutes or until smooth. Divide into 12 equal-sized balls and cover.
Heat a dry skillet, griddle, or comal on medium-high until hot. Place the plastic on the tortilla press and then place between the plastic a ball of dough. Press out the tortilla.
Take the tortilla wrapped in plastic off the press, gently peel off tplastic and place in the hot skillet. Cook 30 seconds on one side, flip it, and cook a minute on other side. It should start to puff a bit. Flip it again and cook 30 seconds on the first side.
Place cooked tortilla in a basket lined with cloth or, if you have one, a tortilla warmer. Repeat process for remaining balls of dough.
Notes
Note: If you don’t have a tortilla press, you can pat the balls into flat discs or roll them out with a pin. You can also place the balls (with the plastic) between two very heavy books and press them out that way.