Client wants to edit DotNetNuke skin and he is not a programmer, so I'm looking for some WYSIWYG skin editor. Either web or desktop solution will do.
Well, this is a tough one really. You can do skin design inside of something like Dream weaver when working with the HTML skin, but then you simply have tokens.
Otherwise, you would need to use Visual Studio or the like and rely on "design time" support of the various skin objects.
What might be the best bet overall would be to use Dream Weaver to edit, and use a test DNN install to see the changes.