Why do you need a microcontroller at all then? Just use one of the radio remote control modules available. They are powered only if a button is hit.
If the end product is the goal (rather than the fun of making it) that seems like the most sensible option. There are various commercial radio and IR remote controls that can be used to switch things on and off - no need to reinvent your own.
Can you link me to any that would do such a simple task? Preferably it would work like a cars turn signal - meaning that when you push on the left button, it stays down until moved back into the center position manually (same for the right position). I can't seam to find anything with my googling.