Q&A for How to Cut an Onion

You are not using the fork to do the slicing; you are using the fork to stabilize the onion instead of using your fingers.

Try freezing the onion for about 20 minutes before cutting it. You can also put on a pair of goggles to protect your eyes against the fumes. If your kitchen has a fan or vent, switch it on, and work right beneath it.

Generally it is sliced in thin slivers to fit on the sandwich.

Put the onions in a Ziploc bag and put the bag in the refrigerator.

You can slice or dice them, but bear in mind the number of edges each piece has will affect how quickly they can burn at the same temperature. Onions cut into slices brown more slowly than diced onions. If you're talking about battering and deep-frying, either separate rings from (thick) slices or separate "petals" from a quartered onion.

The stem. Leave the root (the larger end) intact for an easier grip while you cut.

Cut into rings approximately 1/4" thick, if you are cooking on a BBQ, or if you prefer them a little firmer after cooking, cut them a little thicker.

For a salad, dicing onions wouldn’t be the best option. Slice the onion into thin strands and don’t cut them into squares. You want them thin. Red onions have the most flavor. The type of onion really depends on how much flavor you want.

That depends on what you call "medium", and also how big the pieces are. Most chefs would say one diced medium onion is about two cups, but a finely chopped medium onion can be as little as half a cup.