Dude, don't grind them off
You might be able to unscrew the threaded sections from the mounts, if not Hope and X-Lite sell some alloy jobbies to put over them for MTB bikes that use Disc brakes. Nothing wrong with keeping the V-brake, just change it to a Dia Compe MXII or Shimano BMX V
I would check my GT24 to see if you can unscrew them but it's in the garage and cold