You could use the new BrowserWindowOpener class:
From the API:
Component extension that opens a browser popup window when the
extended component is clicked.
Example:
BrowserWindowOpener browserWindowOpener = new BrowserWindowOpener(new ExternalResource("http://google.com"));
/*
* Apparently, the BrowserWindowOpener method setWindowName uses the HTML5 target
* attribute (no longer deprecated as it was in HTML4).
* So you can use either a frame name, or one of four special attribute values:
* _blank, _self, _parent, _top
*
* browserWindowOpener.setWindowName();
*/
final Button btn = new Button("Click me");
browserWindowOpener.extend(btn);
btn.addClickListener(new ClickListener() {
@Override
public void buttonClick(ClickEvent event) {
btn.setCaption("clicked");
}
});
More information here.