If you don't know the proper technique to cut an onion, one of a couple things could happen. You could either have uneven pieces that look pretty wack, or you can have an eyeful of tears.
DavHax found a quick way to get that onion chopped as easily as possible. All you need is a hair pick and a sharp knife to chop your onions with.
Carefully stick the hair pick into the onion. Cut along the slits so that the onion is held together. Then, once you have even slices, rotate the pick 90 degrees and give your onions a finer chop.
Your fingers will be nowhere near the blade.