Crop figures or create custom bounding box for geographical data

I would like to eliminate the extra white space within the black boarder of the map created by this particular map projection. More specifically I want to eliminate part of the Atlantic Ocean and Pacific Ocean that don't have any data, thus don't contribute to the map. This would allow me to shrink the width of the map and fit more maps into a reasonable space when creating subplots with multiple maps. I was hoping to automate this process by either: 1.) creating an automated crop of the figure (I could move colorbar to bottom of figure so it's not cropped out) or 2.) creating a 6 point lat long bounding box. Right now only the northern and southern latitude and east and west longitude determine the map space, but if there was a 6 point bounding box of some sort, then I could change the east and west longitude for latitudes below a certain number. Any suggestions would be great!