Find the next outlet downstream from the GFCI behind the refrigerator. Then (with the power off) swap the receptacle devices between those boxes, taking care to be sure the GFCI now in the "2nd box on the circuit" is correctly wired. The refrigerator will NOT be GFCI protected this way.
You can find which outlets are downstream of the refrigerator outlet simply by test tripping that GFCI. This won't tell you which is the next one, but it most likely is the closest one. Once you have the GFCI in the new box, test it to be sure it does shut off the others on the same circuit. There should be two circuits with GFCI. Test the other one for correct operation, too. With both GFCIs tripped, every kitchen outlet should be off, except the dedicated one.
You should have the refrigerator (and other heavy load devices like a microwave oven) on dedicated circuits (this is the point to negotiate with the seller). The refrigerator can share with a freezer (as long as it is not in a garage). They do not need to be on GFCI unless the kitchen has a wet material floor (like concrete, or in a garage).
Long and boring, but the proper way...
You will have to see how the cabinet is fastened. If it is screwed on the sides to the "walls" of the housing then you need to remove it before removing the "walls"
If the cabinet is screwed on the back- to the actual wall (even id it has side screws) then empty it out completely and you should be able to safely detach the wooden "wall" you want to move.
In this case you will need pad out the extra space in-between the cupboard and wooden wall you are moving with another piece of wood that will fit. You need 3" inches.
A nice way would be to pad both sides of the cabinet with 2" thick pieces of wood to give you an extra 4". Painting it white will make it look like it should be there.
Then you need to screw from inside the right side of the cabinet through the padded wood into the wood of the existing cupboard -- but not so the screw comes out the other side. You need to measure precisely the length. screw in each corner and centre. Then put the left wall back in and screw from the left side inside the cupboard the same again.
You obviously have a problem with the light switch. IF you got enough space inside you could make a square opening in the side "wall" that you are moving and put the switch in there. The wires will be behind the fridge any way - just insulate them with some flex plastic pipe for wires.
The light switch will have to get moved to something similar like this. You can mount it flush /countersink it into the wall you are moving. The biggest problem is cutting out the hole to the correct size. You can go larger but you cant shrink. So be careful and try to fit it several times.
It is not an easy undertaking- but I would not do it any other way.
If you cant be bothered ...
If you cant be bothered doing it the right way. Then put several wall bolts in the back of the cupboard in the corners and centres. Then remove the left "wall" and put your fridge in.
But this will NOT work if you have a drywall behind the fridge.
Best Answer
This entirely depends on the refrigerator and where the coils and fans are. Older refrigerators were cooled with fins on the back, and depended on convection (heat rising). The heat of the coils would draw air through the lower grille, up the back, and over the top. A modern unit might do all it's cooling with a fan pushing heat out at the front bottom plate.
Samsung's current models require 1" on top, half inch each side. See : http://www.samsung.com/us/support/faq/FAQ00021650/21818/Y/RB197ABPN/XAA
Keep in mind your cabinet is now built to fit just one size refrigerator: just hope that size is available in fifteen years when your current model is no longer repairable due to planned obsolescence. Front venting units are also somewhat less efficient, all other factors held constant.
It's common to have the cabinet above the fridge a bit less deep than the others, to allow for airflow.