Preheat a large heavy-bottom skillet or cast iron flat grill over medium-high heat. You want that pan scorching hot before you begin.
Mix the corn masa in a medium bowl and a sprinkle of salt. Add half the water and mix with a fork until the dough begins to come together. It will be crumbly and resemble sand. Continue adding water until there’s no dry flour at the bottom and the clumps of dough appear larger and begin to come together. You may need more or less than what the recipe says.
Lightly massage the dough with your hands now and work it into a ball. It should feel wet but not sticky and it should not crumble. Do a little test tortilla if you must. If they're too wet, they won't separate from the plastic and may fall apart. If they're too dry, they will crack a lot on the skillet and may have trouble puffing up. Either splash 1 tbsp of water to moisten or a couple tsp of masa to firm up.
Divide the dough into 9 golf ball sized pieces and cover until ready to cook.
Press the tortillas into a thin disc shape using a tortilla press or two heavy pans. Place the dough ball between two pieces of heavy plastic (I reuse a large ziplock bag that I’ve cut in half). They should be almost see through and evenly pressed all around.
Remove the tortilla from the plastic wrap by pulling one side away then flopping the tortilla into your other hand and peeling the other side of plastic off the back of the tortilla.
Place the tortilla on the hot skillet gently, making sure you don’t burn yourself or that you trap bubbles under the tortilla. Holding the tortilla in the palm of your hand, gently drape the tortilla over the skillet, then flipping your hand over in a gentle backhand motion, release the tortilla onto the skillet.
Cook for 30 – 45 seconds on one side, flipping when steam begins to appear around the tortilla and the sides just begin to curl up.
Flip then cook for another 45 seconds to 1 minute 15 seconds until done. It’s done when you flip the tortilla over again to the original side and press down on it and it puffs up. If it doesn’t, flip it back over and give it another 10-15 seconds. If it still does not puff up but appears cooked, set it aside anyways. Not all of them will be perfect and it’s better not to overcook them.
Place the cooked tortillas in a tortilla warmer or under a warm towel. The steam allows them to finish cooking and become pliable.
Finish cooking all the tortillas, leaving them stacked until ready to eat.