Select the Textbox (or Placeholder) properties of your incident number, go to the "Action" part und enable there "Go to URL".
The I use the following SSRS expression for the "Select URL:" field
This formula requires that the RecId of the incident is included in the associated data set as well as the existence of a parameter called "Tenant" that holds the URL "prefix". This parameter is usually defined as hidden in the Ivanti/HEAT report definition and set to "$(SecureServerURL())" (or just "£ServerURL())"). This way the same report can be used unchanged in different staging environments.
Hope this helps,