The Drs. Foster & Smith catalog has some freeze-dried crickets and I was wondering if they can be fed to goldfish.

I don't see why not. Many goldfish eat flies and other insects. Hmmm let's see what others think!

Depending on their size, you may need to break them up. I would
think they'd just be the occasional snack rather than part of the main
diet.

Fish eat bugs, so feed them as a special snack. Just like bloodworms, they too are insects.