Combine the flour, salt, and shortening in a large bowl and mix together until crumbly. Add water slowly while mixing until you can gather the dough into a ball. Transfer the dough to a lightly floured surface and knead until smooth (about 5 minutes). Cover and set aside to rest for 30 minutes.
After resting, 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 or cook immediately.
To cook the tortillas, heat a heavy skillet or griddle 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. You can also freeze these for up to 3 months!