Mala is responsible for the starting window.
I can't remember if there is a way to disable it, but there is an option to replace it with a fullscreen picture.

Look through mala.ini and the tabs in mala options for an option to turn it off.
If no luck there, you could try creating a completely transparent image and make that your fullscreen starting picture.
Mala doesn't handle transparency well in other aspects, so it may or may not work here.
Not sure what would happen if you point mala toward a bad or non-existant file as the starting picture.
If it just doesn't load anything and doesn't give any error messages, that could work.