You will have issues opening up another window under the current platform (security concerns). What you may want to do is capture content via an ajax request and load it directly within the application itself. You can do this with the OpenSocial gadgets.io.makeRequest method. Alternately, to mimic the behavior of an opening window, you can have a floating div on top of your content which loads the content from the makeRequest ajax call. This will appear as though the content is a new window but will still maintain the security of the app.
- Jon