In a medium bowl, mix the masa, salt and melted lard, butter or vegetable oil together with your fingers or a whisk.
Slowly pour the water into the masa mix while stirring with a wooden spoon until the dough becomes a ball.
Turn the dough out onto your work surface that is lightly floured with some masa harina.
Knead the dough for about 1 minute until smooth and no longer sticky. If the dough is too dry, add a bit of water to moisten. If the dough is too sticky, add a bit more masa until the dough is easy enough to form a ball in your hand.
Divide the dough into 12 (1 ounce) portions and hand form each into a smooth ball. Make the balls smaller if you want small tortillas.
Place them on a baking sheet, cover with plastic and let them rest for thirty minutes. (If you are in a hurry, you can skip this step. Letting it rest gives the dough an opportunity to absorb the water.)
After the dough has rested, preheat a cast iron skillet or any high heat tolerant skillet over medium-high for five minutes, then reduce heat to medium.
Place dough ball between two pieces of plastic wrap and press in a tortilla press. I don’t have a press so I laid the the dough in the plastic wrap between two small wooden cutting boards and pressed down as evenly as I could. Press until the tortilla is about ⅛″ thick.
Peel away the plastic carefully while holding the tortilla flat in your palm and transfer into the hot skillet.
Cook the tortillas until you see brown spots appear (about 1 minute) and then flip with a thin metal spatula, and do the same on the other side.
Transfer the cooked tortillas to a baking sheet and cover with a damp kitchen towel to trap the heat and moisture.
Serve immediately or let cool and store according to the Gr8 Tip below.