Under ubuntu, you already have a built in recycle bin (the .Trash directory). I dunno the situation under other linux distros.
For windows, the the dokany project (which cryptomator is using for mounting the vault) has an option for an recycle bin, but currently it is deactivated because it causes some problems. Maybe in the future it is included as an option.
Until then under windows you have to stick with WebDAV or find some way other neat trick to get it working.