Considering the amount of time that we’ve all spent incorrectly chopping onions, we figured everyone could use a good how-to lesson. You will save time and also derive a modest pride in learning the proper technique.
Peeling an Onion:
1: Halve the onion lengthwise, from the top down through the root.
2: Grab hold of the skin along the cut edge and slip the peel from the onion half.
Dicing an Onion:
1: Set the halved, peeled onion, cut side down, on a cutting board. Using a sharp knife, make several vertical (parallel) slices (depending on the desired end-result – from finely diced to roughly chopped) almost to the root end.
2: Then, slice across the grain to make your preferred-size pieces.
Sometimes showing is much better than telling. Pardon the slightly saccharine presentation, but this video clip [1] offers a nice tutorial. For practice, here is a good recipe - Onion Soup Gratinee.