Combine the flour, salt, and shortening in a large bowl and mix together until crumbly, as for pie dough. Add water and mix until you can gather the dough into a ball. Transfer the dough to a lightly floured surface and knead until smooth and elastic, about 5 minutes. Cover with plastic wrap and set aside to rest for at least 30 minutes or up to 2 hours.
To form the tortillas, divide the dough into 12 equal portions. Roll each portion between the palms of your hands to make a ball. On a lightly floured surface, roll out each ball into an 8 inch circle. Layer the circles between sheets of plastic wrap as you go.
To cook the tortillas, heat a heavy skillet, griddle or comal over high heat until beginning to smoke. Place a tortilla in the pan and cook for 30 seconds. Turn and cook on the other side until slightly puffed and speckled brown on the underside but still soft enough to fold, about 30 seconds. Remove and continue until all the tortillas are cooked, stacking them as you go. Serve right away or cool, wrap in plastic wrap and refrigerate for up to 3 days.