Can i hide layers?

[LunaMoo]

You can't "hide layers" because there are no "layers" in PSP games nor any other modern games unless specially designed that way.

GE Debugger is a debug feature available in windows version of PPSSPP from under debug menu(or by pressing ctrl+G), it's a very powerful tool which allows checking and changing how PSP game draws it's graphics, without learning more about that you'll probably not be able to use it for much other than as said before stepping through draws until what you want is shown. You should also make sure you're using fairy recent PPSSPP and not the outdated release version as ability to dump images from GE debugger was a new addition.

If all you care about is removing some 2D graphics from the screen, you can also use texture replacement and replace whatever you don't want with a 1x1 texture containing only transparent pixel or something alike. That would work on all platforms PPSSPP runs at as long as it's not using Qt build(since such builds doesn't have Texture Replacement and nobody really cares much since the platforms with Qt also have SDL builds;p).