Because we have two small pistons instead of one big one, They're easy to push back in, and don't require a "C" clamp or other special tool. You'll need to do this if you're replacing your pads with new ones (I went with Hawk ceramics).
You can use a block of wood and your thumb to walk the pistons back into the caliper. Don't forget to loosen the brake reservoir cap and place a towel around it to catch any overflow while you're pushing the pistons.
"If it's too loud...well, you know the rest."