Delicately flavored sweet onions (Vidalia and Walla Walla) are best for cooking, especially in recipes that call for raw or caramelized onions.
No More Tears
Slicing into raw onions releases the sulfur that causes those stinging tears. Grown in low-sulfur soils, sweet onions contain considerably less sulfur than other onions, so they aren't tearjerkers. And they're also less likely to cause indigestion.
Thin-skinned sweet onions are more fragile than other varieties and need a little extra care to prevent bruising. They do best stored in the refrigerator, wrapped in paper towels to keep them dry. If you have part of an onion left over, tightly wrap cut onion in plastic wrap and refrigerated.