This is the simplest and quickest way to dice an onion. If you don't want to cry--just breathe through your mouth the entire time. If you don't breathe through your nose you should be fine.
**Disclaimer 1: This project involves sharp knives. If your knife is dull, you have a tendency to chop off your appendages, or you are small child, you should not attempt this project.**
**Disclaimer 2: If you don't follow the breathing instructions, and this makes you cry, make sure you wash your hands before rubbing your eyes...then find a shoulder to cry on...**
Step 1: Slice off the top
Slice off the top of the onion--do not cut off the root end!
Step 2: Peel off the skin
Starting at the edge of the skin where you just cut, peel off the outer skin, down to the roots.
Step 3: Make 1st set of parallel cuts
Holding the onion firmly, make parallel slices from the top towards the roots, without cutting completely through. Get as close to the roots as possible without detaching the section that you're cutting. Make the cuts as far apart as you want your diced pieces to be.
Step 4: Cut cross sections
Hold the onion so that the slices you made stay together. Make the same series of slices perpendicular to your first set of cuts. From the top, your onion should look like a grid.
Step 5: Slice your heart out.
Holding the onion together, lay it on its side, and carefully slice down. When you get close to the roots, you can lay it cut-side down and slice around the roots to use the entire onion.