For frying: about 8 cups Peanut, corn, or canola oil (need 3 inches depth in a large pot or electric frier)
Any taco fillings you like: beef, shredded chicken, refried beans, avocado, etc.
If using masa harina, combine in a large bowl: masa harina, water, salt. Mix well until you have a soft, smooth dough that does not stick to your hands. If it's sticky, add a tablespoon more of masa harina. If it's dry, add a few drops of water at a time until it forms a ball.
Roll your dough into a 16" long cylinder and cut into 16 pieces. Roll each into a ball. Line a tortilla press with plastic wrap or a food storage bag that's been cut open. Lacking a press, use a heavy pot and a sturdy counter top to press them.
Press each ball between plastic until about 5" across and 1/8" thick. Lay out in a single layer as you press them.
Heat your oil to 375°F. Fry tortillas one at a time. They will sink to the bottom, then rise up, puffed. Use a spatula to form a crease in the center, pressing them down under the oil for about 45 seconds, until golden brown. Your first few may break, but you will get the feel for it pretty quickly.