Great idea about the curtain. Get an extra long curtain rod so you can hang a panel completely over the electrical box and another to balance it on the right hand side. Choose a fabric that has a combination of white and at least one colour. Then paint the room the main colour you have in the curtains. It will look bright and cheerful.

I would not put a curtain! Find a bright piece of artwork, maybe a poster, and hang it over the light box.

Paint the kitchen a color that makes YOU happy!

And your place is not ugly, it needs a clean up. After you paint, I would look into changing the hardware (looks like plastic on the pics) to something fun, maybe brass, or the Anthropologie funky style. Then wait 1-2 weeks before making other changes, to see what the use of the kitchen really needs.