
Whisk the masa harina and salt together in a large bowl. Pour in 1½ cups of warm water and stir until a shaggy dough forms, then knead by hand for about 3 minutes until it's smooth and no dry masa is left. It should feel like soft Play-Doh. If it cracks when you press it, work in more water a tablespoon at a time. If it clings to your skin, dust in a little more masa harina.
Portion the dough into 12 balls, set them on a plate, and drape a damp cloth over them so they stay moist while you work.
Heat a nonstick skillet or comal over medium-high until it's good and hot. While it heats, trim the seams off a large zip-top bag to get two flat sheets of plastic, or cut two squares of parchment.
Sandwich a dough ball between the two sheets on the tortilla press and flatten it to about 5 to 6 inches across. Peel the plastic away and lift the tortilla into your hand.
Lay it on the hot skillet. Give it 15 to 20 seconds, flip, another 15 to 20 seconds, then flip once more and cook 30 seconds a side. It should puff on that last flip. Repeat with the remaining dough.
Move the cooked tortillas into a tortilla warmer as you go, or wrap them in a clean kitchen towel and slip them into a large zip-top bag so they stay soft.
Serve right away, or cool and store wrapped in the fridge for up to 5 days.