1. Remove them ... I think they are in DTA/anims.pbo. But I wouldn't recommend it. Apart from all the usual caveats of messing with the game the actual consequence is messy. Instead of an anim, behind the main menu you get the last mission that you played in the mission editor. Usually this means that mouse clicks fire shots as well as selecting menu items. I have no idea what happens when you first start the game, I wouldn't be surprised if it crashed.
Perhaps you could make your own anims and replace the standard ones with those.
2. alt tab works, you don't even need to pause the game although it is desirable. You can copy and paste between text files and the mission editor.
Oh, and this is request is more or less in the right place ... I'd have put it in Editing: General rather than Editing: Advanced but that's not a big deal. If in doubt, always go for the General board.