OK. I can answer my own question now. It is really easy! It takes only about 10 minutes. Tools needed: torx bit screwdriver, small pliers, possibly some 200 grit sand paper.
1. Remove safety spring-clip from the rear of the bolt (on the side of the wheel). Just push it out with a flathead screwdriver
2. Remove bolt (using #25 torx driver). This is the bolt that goes through the "eye" of the brake pads
3. Pull out the pads. They just come out when pulled gently by hand towards the rear of the bike.
4. Put in new pads. May want to sand them flat/clean gently over some 200 grit sandpaper on a flat surface (my new pads had some paint drops on the pad material that this gentle sanding removed)
5. Screw-in the bolt. It maybe good (or not?) to use some anti-seize paste (I did not, does not look like there was one on the bolt from the factory). Torque value unknown, but be quite gentle - probably something like 10lb/ft (hand-tighten firmly with a regular screwdriver kind of torque).
6. Reinstall safety clip
7. Test your ride carefully!
I wish I knew the torque value for the bolt though. Anyone have that info?
Is there a thread/instructions on how to replace the rear brake pads on a '15 S/DS/R? Could not find it here in the forums and in the owner's manual. Do I have to pivot the caliper up first, or is it just removing this one bolt that goes through the "eye" of the brake pad?
Thanks!