Combine flour and salt in your food processor and using the regular blade, pulse 3 times to mix. If you don't have a food processor, you can use a instead.
Add the cold butter and process until you have a crumbly flour mixture, then add vinegar and lemon zest.
Process until you have coarse crumbs, then start adding the cold water (be sure it's cold and not room temperature) 1 tablespoon at a time. When it starts to form a ball of dough, you can stop processing.
Place your dough on a floured surface (I just use the counter) and form it into two discs. Wrap them in plastic wrap and refrigerate for at least 1 hour.
When the hour is up, remove one of the discs from the fridge. Add a little flour to your work surface, then starting from the middle and rolling outward, roll dough with a rolling pin until it forms approximately a 12-inch circle (or is wide enough to cover the pie plate all the way around).
Place in a 9 inch pie plate and crimp the edges all the way around.
Use a fork to make holes on the bottom of the crust.
When you're ready to add the top crust, roll the remaining dough into another 12 inch circle. You can lay this layer over the top or cut it into strips, lattice style.