Ok! This peaked my curiosity since I too love the sweet vidalia onions!
This is the information I found:
The key to preserving Vidalias, and to prevent bruising, is to keep them cool, dry and separated.
There are several favorite methods of storage Vidalia Sweet Onions.
Store them in the refrigerator, wrapped separately in a paper towel. This method is expensive and takes up precious refrigerator space, but can preserve Vidalia Onions for as long as a year.
Store them in the legs of clean, sheer pantyhose. Tie a knot between each Vidalia and cut above the knot when you want one. Hang in a cool, dry, well ventilated area. On elevated racks or screens, not touching and in a cool place.
Vidalia Onions can be chopped and dried in the oven. Use the lowest setting and remove when thoroughly dry but not brown. Store at room temperature in airtight containers. Vidalia Onions can be frozen. Chop and place on a cookie sheet in the freezer. When frozen, remove and place in freezer containers or bags, and seal. This allows you to remove the amount you want when you want it. An alternative is to freeze whole. Jumbos can be peeled, washed, cored and dropped in a plastic bag. Once frozen, they can be removed like ice cubes. Freezing changes the onion's texture, so frozen onions should be used for cooking only. Whole frozen Vidalias can also be baked.