Pierre,
In this case it's really helpful to use a network packet monitoring tool to determine what operations are using the most bandwidth. I've seen SQL queries go from gigabytes over the wire down to a few hundred k (which is what you expect from most if not all your queries) after just a bit of tuning.
(I'm talking about gigabytes of network traffic for a returned result set that, in itself, is just a few hundred k. The reason is entire indexes and then a sub-optimal intermediate result set is being returned to the workstation.)
By far the best way to limit data over the wire is to eliminate non-discriminating indexes, like indexes on DELETED(). See FPA May 1999 for an article by Chris Probst about this. See also
http://fox.wikis.com/wc.dll?wiki~NonDiscriminatingIndex for information about non-discriminating indexes.
Also, indexes aside, the way a SQL statement is structured can make a huge difference.
By the way, Citrix with Metaframe will run over Novell, no sweat. It's vanilla MS Terminal Server that's far less portable than Citrix+MetaFrame. See
http://fox.wikis.com/wc.dll?Wiki~CategoryThinClient for more about this.
Andre