Place the graham cracker crumbs in a food processor. Grind until crackers become a fine crumb. Transfer to a medium-size mixing bowl.
Add the sugar and salt, and mix with a spoon until well combined.
Pour in the melted butter. Stir until all the crumbs are evenly moistened.
Pour the crumbs into a 9-inch pie plate and spread into an even layer. (If your plate is smaller, you'll have a thicker crust.) Using your hands, or a flat-bottomed measuring cup, press down on the graham cracker crumbs. Start in the center of the pie plate and work your way out and up the sides. You need a stable bottom for the pie first.
Bake for 8 minutes. Remove from the oven and let cool off at least 10 minutes for pies that need to be baked. Cool completely before filling for cold pies.
Notes
If you don't have a food processor available, place the graham crackers in a gallon ziploc bags and beat the crap out of them until you get a fine crumb. Continue as directed.