How to stop/unload a specific IIS Application (hosted within a specific Site) in order to release the server's resources?
The IIS API (Microsoft.Web.Administration) seems only to allow stopping the entire Site:
Stop/Start WebSite in IIS (6.0 and 7.0) programatically
UPDATED:
I have managed to resolve this issue via an alternative way:
Configure an Application Pool to Recycle after Reaching Maximum Virtual Memory Usage (IIS 7)
As a result, a particular pool is recycling automatically.