Currently there is no way to send a link. You might want to consider using the Publish feature to generate a link and then send that as a scheduled notification.

The point behind sending the report as an attachment rather than a link is that it is a snapshot in time. Sending someone "Incident priorities for the last 30 days" would be 30 days from the time it was sent, not from the time someone decides to open their email and look at it via a link. We all know someone who has thousands of unread email in their inbox, right?

If you feel it makes sense to send an email link and don't want to construct your own link to a published report and scheduled job to trigger that report periodically,

I invite you to open an enhancement request! Our product managers DO listen.

Enhancement requests: Tell us how you would improve the ServiceNow product

Creating a Scheduled Job - ServiceNow Wiki

Scripting for Email Notifications - ServiceNow Wiki

Email Notifications - ServiceNow Wiki