Opera mini is a java application.. no java support on the Nokia tablets yet. No ETA either, unfortunately.

For minimising data traffic on my N800 when on GPRS I have privoxy installed, and the bt pairing network configuration is permanently set to use the proxy. This'll filter out a lot of large images and all banners automatically. In addition I also often set 'load images' in Opera to 'only downloaded' (or whatever the English locale translation is).