Bring a large pot of water to a boil. While the water is coming to a boil, trim off the root ends of the onions. Prepare a large bowl of ice water.
Place the onions in the boiling water and boil for 2 minutes. Drain. Submerge the onions in the ice water and let sit, stirring with your hand once or twice for a few minutes until cool enough to handle.
Use your fingers to pinch the stem end of the onions and the skin will loosen and then slide right off.
Notes
Make sure to have the ice water ready before you add the onions to the boiling water.