Because of the page lifecycle within Kentico you won't want to mess around with some of those things. Some webparts/controls load once and then need to reload the data because of the lifecycle.
If you're concerned with too many calls or performance, you can always set your caching to be a greater time per webpart or for the whole system. If you simply want to stop the additional postbacks, you'll have to program around them because that's how Kentico works.