Both corn tortillas and flour tortillas are widely used in Americanized Mexican cooking, but the original ones were of the native corn only, and except in Northern Mexico, corn tortillas remain the norm and the staple.
Put together in a large bowl:
1 ℓ masa harina *
2.5 ml salt
625 ml hot but not boiling water
*Masa harina (corn flour) can be purchased in most supermarkets in the USA. If you cannot find it where you are, you can grind your own from cornmeal with a flour grinder. Put the grinder on a fine setting, and feel the resulting masa to see if it is soft. If not, run it through the grinder again until it is.
Mix with your hands to make a dough that comes together in a soft ball. Continue mixing and kneading until the dough is elastic enough to hold together without cracking, about 3 minutes. If using right away, divide the dough into 18 equal portions and cover with plastic wrap or a damp towel. If making ahead for later use, wrap the whole ball in plastic wrap and refrigerate for up to 1 day and then divide.
To form the tortillas, place a portion of dough between 2 pieces of plastic wrap. Press with a tortilla press or roll out with a rolling pin into a circle 15 or 18 cm in diameter. Use your fingers to smooth any raggedy edges. Continue with the remaining portions until the dough is used up.
To cook the tortillas, heat a heavy skillet or griddle over high heat until it begins to smoke. Peel the plastic wrap off a tortilla and place the tortilla in the pan. Reduce the heat to medium-high and cook for 30 seconds. Turn and cook on the other side for 1 minute. Turn again, and cook until the corn tortilla puffs a bit but is still pliable, not crisp, about 30 seconds more. Remove and continue until all the corn tortillas are cooked. Serve right away as this is when they are the best.