It's pretty hard to do this, because the splash screen is baked right into the editor executable file. So you can't just swap out a .gif file and get your own splash screen. And I couldn't find any startup command parameters that would suppress the splash screen.
One thing I found that seems to work is to launch it as an ActiveX object. If you create a file called startepic.js, containing the following code:
Actually, I was able to find the splash screen by opening the executable in MS Visual Studio. But I would definitely not want to recommend to anyone that they try to hack the exe binary just to tweak a splash screen. I'm pretty sure that would void your warranty, at the very least, and might well break the executable.