Cydia usually takes a painfully long time to load when you launch the app. An easy way to speed up it's loading time is to disable Internet (wifi / 3G) on your device when you are launching the app. Having no connections available, the reloading/refreshing will stop relatively quickly with an error message ("Unable to connect"). Now you can switch back on the connection using SBsettings and proceed with whatever you want to do. Obviously, this is assuming you have SBsettings and that you do not wish to search for and download updates on that particular instance.