I use XFCE and have removed apps that i don’t need, tho eventually they keep up installing by them selves again, apps like TigerVNC and Xterm.
These are recommended packages from the XFCE pattern. Personally I don’t see the need to remove such packages - I simply don’t use them until something else uses them -, but if that’s what you prefer, it’s best to remove them, then lock them, f.e.
sudo zypper rm xterm
sudo zypper al xterm
Another option you have, is to set OnlyRequires to true in /etc/zypp/zypp.conf, but that would change the overall behaviour to not install recommended packages, only required ones.