If you use moves such, Giga drain or any other move with healing effect against a pokemon with "Shield dust" ability, The healing part won't trigger just the damage
I haven't tested if moves that does no damage (such as "Thunder wave") trigger if used on pokemon with that ability, but I suspect it doesn't.
I haven't tested if moves that does no damage (such as "Thunder wave") trigger if used on pokemon with that ability, but I suspect it doesn't.