I'm using Desktop FullScreen Web Browser for this.
I can't seem to get it to open gmail-links automatically in that app, but at last it works to manually copy the url and paste it into that browser.
I do a lot of linking to specific mail-threads. Most of the time I'm opening these on my desktop, but once I've been on the go before I found this app it was a real pain and it's impossible to find the right mail from the url alone in that case.