These are usually the most mild of the onion varieties, so we like to use white onions in salads and on sandwiches. Basically, if you’re going to eat an onion raw, the white onion is what you want to reach for. And while they're pretty mild on their own, you can further tame their flame by slicing one thinly and giving it an hour-long soak in cold water—they'll be so sweet, you can practically eat them like a salad.