To "untriangulate" a surface, you can select the adjacent triangles/surfaces and use "Surface | Combine" (or just press "c").
As far as rotation, by default, the camera should rotate around 0,0,0 --- if you perform a "Look at selection" (Ctrl+G), your camera will pivot around the center of the active selection (at the time you issued that command).
Not sure if there's a command for resetting the camera to 0,0,0, though? I would end up creating/setting an object to 0,0,0 and issuing another Ctrl+G, but .....
hth
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