A stay-forever-fresh-radioactive-kosher-meal-box from FNJ to ICN.
Who can find me the shortest official flights between the 2? (Just for fun)
When you say official, I presume you mean non-charter flights.
Air Koryo (official carrier of DPRK) as well as Air China, only have 3 flights a week from FNJ so you're a bit limited. One of them is Shabbos, which leaves you with 2.
Not sure when you want to go, but for Thursday 5 August here are the flights:
FNJ-PEK 10:30-11:30, Air Koryo
PEK-ICN 11:50-2:55, China Eastern, China Southern or Korean
If Air Koryo has similar prices to Air China, the FNJ-PEK leg will cost $39,715.
If you fly cargo (literally, not as in slang for economy) or you are just sending your "A stay-forever-fresh-radioactive-kosher-meal-box" by itself then Air Korjo has direct flights.
PM me if you need more info
Btw, I hope that whatever you were looking for a shutaf for has nothing to do with the above country...