Trying to wrap my head around how this carb slide works. Is it like a Windex spray bottle pump/squirter? I know if theres a crack or hole in tube between liquid in bottle and the air the pumping mechanism looses prime since its drawing in air instead of fluid.

No, it is not a squirter of pump.    It works like a syphon type paint gun or the old fashioned  fly sprayer.  I can explain it to you but I can not understand it for you..