Why are smaller wings in the front with these VTOL aircraft?
It's because with the canard configuration, the smaller stabilizing surface is a lifting surface instead of the down force surface of a conventional tail. 

(A regular tail airplane is a seesaw with someone sitting on one end and another pushing down at the other; a canard airplane is more like a table with most of the weight at one end where the fat legs are and skinnier more lightly loaded legs holding the other end up.  Canards get their pitch stability from having a steeper lift slope at the canard surface, whose airfoil is chosen to achieve that purpose, so the nose will rise with increasing speed and drop with decreasing speed).

So if you want to as much vertical thrust as possible from the available flying surfaces, it makes sense to use the Canard configuration where all the surfaces are lifting.  Canards are nothing new; the Wright Flyer was the first.  You don't see them everywhere because there are significant limitations, but in a VTOL configuration like this, the Canard layout is mostly a plus.