In a food processor combine 2 3/4 cups of the flour (reserve the remaining flour for rolling out the dough) with the lard or shortening. Pulse several times until the fat is evenly distributed throughout the flour and no particles of fat are visible. Dissolve the salt in 2/3 cup of the warm water. With the machine running, pour the liquid through the feed tube in a steady stream and stop the machine once the dough has come together in a ball. Feel the dough, it should be a medium-stiff consistency, not too firm but not as soft as most bread doughs. If the dough is too stiff, divide it into several pieces, sprinkle with 1 or 2 tablespoons of the remaining water and process again until a ball forms.
Divide the dough into 12 portions, roll into balls and place on a flat surface or plate. Cover with plastic wrap and allow dough to rest for at least 30 minutes.
On a lightly floured surface roll each ball into a 7-inch circle by flattening the ball of dough, lightly flouring it, and with a rolling pin rolling forward and backward over the dough, then turn it a sixth of a turn and roll forward and backward agaiy
Adapted from a recipe by Rick Bayless, Authentic Mexican