Leftover canned tomatoes will keep in the fridge for up to a week, but for best results store them in a glass jar. You can add sliced or chopped garlic, shredded fresh basil, and some good olive oil to drained whole canned tomatoes* so they’ll keep better.
Green tomatoes will ripen best in a cool, dark location. That traditional sunny windowsill just shortens the time they have before rotting. One source* suggests ripening the end-of-summer last picking by arranging the tomatoes on a baking sheet, covering them with newspaper, and tucking them under the bed.
How to dry tomatoes, including how to get all those skins off.
*How to peel a peach : and 1,001 other things every good cook needs to know / Perla Meyers. Wiley, c2004. ISBN: 0471221236