I know this is an old question, however, I've just found how to do this with Windows/TortoiseSVN.
As a comment suggested, you can't "delete" a revision, but what you can do is make a more current revision that is the same as the revision you want to revert to.
- Checkout the HEAD of the repository for the directory you want to revert the revision from.
- Load the "Show Log" view in TortoiseSVN for the highest level directory you want to revert (e.g. "Trunk").
- Right-Click the revision you want to remove NOTE: this is the revision you want to remove, not the one you want to revert to.
- Select "Revert changes from this revision".
- Click "Yes" at the prompt.
- Update the checkout as normal, but to "HEAD".
- Commit it back.
You will then to go to everyone else who has it checked out and get them to update and make sure to remove any new files.
Also, you'll need to make sure that everyone knows what that revision was and potentially update the description.