Preheat oven to 350 degrees. Place gingersnaps in a ziploc bag and mash with a rolling pin until finely crumbled (you could also use a food processor or a blender). Stir in spices. Add just enough melted butter to be able to form into a ball that sticks together. Press evenly into a 10 inch pie plate. Bake for 10 minutes and remove from oven.
While crust is baking, beat eggs, sugar, salt and spices until smooth. Add pumpkin and beat well. Gradually add the evaporated milk. Pour into pie crust and bake 40 minutes. Cover edges with foil if they begin to brown too quickly. Lower temperature to 325 degrees and bake an extra 15-20 minutes until a toothpick poked in the center comes out clean.