I'm expanding cursor to multiple lines with CTRL + ALT + Up however I'd like to skip few lines here and there. Something like press CTRL + ALT + Right arrow to skip a line and CTRL + ALT + Left to undo that skip. Where can I hack this change in? What files should I be looking at?
If you're wanting to skip blank lines, my Sublime Extras extension has a different but totally usable approach (see third animated png).
If that's not good enough for you, see the add_selections file for a good start.
Thank you for the pointer. I'll take a look at it.
You might want to take a look at the PowerCursors plugin. It allows you to remove some of the cursors you don't want and/or adjust their positions without moving other cursors.