Congrats on the new kitchen toy!
My mom gave me a dehydrator a few years ago. I need to use it more.
The National Center for Home Food Preservation does not recommend preserving dried tomatoes in oil at home because of the risk of botulism. You can dry them, store them and put them in oil for a few days before you want to use them. Here's more information: http://nchfp.uga.edu/tips/summer/hom..._tomatoes.html
Or there are lots of other ways to preserve them. I like to cut them in half and grate them on a box grater, then freeze them in two-cup portions. Then I have fresh-tasting tomatoes to use in any dish that calls for a can of diced tomatoes.