Cut onions with a particularly sharp knife to reduce "crying." This effect is caused by the sulphur in the onions reacting with eye moisture to produce (very weak) sulphuric acid that the body washes away with tears. The less you tear the membranes of the onion, the less sulphur gets into the air. Wearing glasses, sunglasses, or safety goggles can also help by limiting the sulphur fumes' access to your eyes. For big projects or extra protection for sensitive eyes, invest in a good pair of swimming goggles, sized for adults. If anyone laughs, invite them to take over the chopping.
To tone down the pungency of an onion, soak it in ice water for half an hour before using it.
To peel pearls onions, drop them into boiling water for about 30 seconds, then into cold water. Trim the root end and squeeze the onion toward the stem and it will pop free.
Many believe leftover onion -- not used the same day it's cut -- will attract and collect germs. There's some scientific evidence to support the idea, so consider chopping up the whole onion and freezing what you don't use right away -- or even chopping and freezing several onions at once. It can be very convenient to have a stash of chopped onion all ready to toss into the soup kettle or frying pan.
I'm told this chop-and-freeze technique works with celery as well, also just for cooking. It'll lose its crispness but not its flavor.
