Heat a large pot of boiling water.
Drop the pistachios in the pot when the water comes to a rolling boil. Let the pistachios boil for about a minute or so, at which point you will notice the peels lifting off. The goal here is not to boil the pistachios til they are mushy, after all.
Strain out the nuts and drop them into an ice bath immediately to chill them.When the pistachios are thoroughly chilled, the peels should just lift off. This is a slow, tedious task. I suggest you peel them while watching Netflix. You can also rub the blanched pistachios in a kitchen towel to loosen the skins, and then the skins might just rinse off at that point.
How you choose to get the peel off in the end is your choice, but the point is that to skin hazelnuts, you toast the hazelnuts to lift the skin off, then rub them. But to skin pistachio nuts, you have to blanch the pistachios and shock them in cold water to lift the papery brown pistachios off, revealing the green pistachio nuts.
I let the peeled pistachios air dry on sheets of paper towel, and I use them within a day. Some dry out peeled pistachios in a low oven to remove moisture for longer term storage (try baking them at around 200 ºF for an hour or two, which I realize is a very long time, but if you did a big batch of pistachios, it will take over an hour).