You can't do this unless you recompile the game. If you are worried about window size, you can go into settings and turn on double scale mode. Fullscreen might also work but it's a bit annoying.

You could also try a mod like this: https://powdertoy.co.uk/Discussions/Thread/View.html?Thread=22025
Saves made in this won't work for others though, and you won't be able to open any online saves.