How do I prevent RC from creating these massive “filler” parts of the mesh? I would much prefer if they would remain as holes.
Thanks.
RC by default creates a watertight mesh.
Use the filtering tools available to remove those large triangles.
I hereby offifically apply for this question to be inducted into the Hall of Fame, aka FAQ… 
Hi Gӧtz,
your wish is my command 
We will add it to the FAQ as soon as possible.
Excellent!