Park MTB at work without Kickstand
We had those parking stands at my old workplace. They suck:


They make it impossible to lock  both the frame and a wheel with U-locks. 
Fat wheels don't fit.
If they do fit, if someone or something (like a strong wind) pushes on your bike, it'll easily taco your wheel.


You should petition for better bike stands that are more secure. 

In lieu of that, you could:


park your bike up against the wall and perpendicular to the stand, and use two u-locks to secure your front wheel and frame/rear wheel (even then, you'd need a pretty big u-lock to make it to the ground from the bottom bracket/rear wheel). You would take up about five parking places and might earn you some enmity
do the above, but remove your front wheel and lock it and the rear wheel and frame with a bigger U-lock
take your bike inside. When they complain, complain back about the parking stand
Find a nearby lamppost or parking meter
Get a folding bicycle