As they say there are no dumb questions when it involves aviation especially if yr airborne!:-)
Part of the original Q says 'we have two wings'......well technically that's correct for say a modern day A/C but essentially there is only one wing just interrupted by the body of the machine. What about a parasol wing? That's just one wing from tip to tip uninterrupted so it could be said for aerodynamic purposes there's only one wing not withstanding the other associated issues with this common arrangement such as parasite drag or interference drag.
Typically having the only stall warning device on the L/H side as for say Cessna means the PIC whom usually sits in the L/H seat can see the probe for a variety of reasons. Obviously a low wing machine doesn't have this feature.
Both wings (if you want to call them that for clarity) in a perfect world would stall at the same time as they are considered as one being equal lift either side of the body but obviously one side of the wing will stall first due all sorts of reasons such as bank angle etc but for simplicity of design in light A/C there's only one stall warning device.
Lots of good answers here.
'GG' the original poster re computer controlled planes is quite correct & that's exactly why modern day planes like the Airbus won't allow under normal law a pilot to exceed the planes set parameters,keeping it from stalling being just one of them, hence that comment computers are in control is essentially correct & not the dumbest Q
.
Wmk2