The mixture will be a bit crumbly before baking, when you're pressing it into the pie pan, but will form a nice crust after it's baked and cooled.
I grind the crumbs in a food processor, but I don't mind if they're not too fine. A little extra texture is sometimes appreciated. If you don't have a food processor, you can put the pretzels in a sturdy zip-top freezer bag, seal it (expressing the air out of the bag as you do), then running a rolling pin over the pretzels to crush them.
Storage: This crust can be refrigerated for up to five days, baked or unbaked. It can also be frozen for up to two months.