I've used Opus on iPad with Microsoft's remote desktop (RDP), and everything worked great and touch-friendly, for example the lists in Opus could be scrolled with finger anywhere (natural scroll) not just via scrollbars etc.
The main reason for this is that Opus tries to use the Windows' common controls wherever possible, so we get features like this "for free" automatically (powered by Windows itself).
I've never tried it on the Surface natively though, so can't guarantee anything myself.
FWIW I've just found an old report that it seems to work nicely on Windows 10 Pro tablets: