Father Skywalker said:
No. After Alderaan was destroyed by the first death star (and despayre too, if U count the EU/the Expanded Universe)
However the empire tried to destroy Yavin IV, Endor, and Chandrila (senator mon mothma's home-planet) and the planet Mon Calamari (home to the mon calamari aliens), as self defense, a retaliation to the rebels. They destroyed 2 planets-the planets alderaan and depsayre, to test out the first death star and keep the galaxy (not just the rebels, but ordinary civilians too) in line with fear of its power. After the destruction of the first death star, the second death star was never used, or even attempted to be used, in an offensive attack/strike on an innocent civilian planet.....
Surely though the DSII was never used because it was never finished... Why would the Empire build a Death Star (the name alone should show that the Empire aren't exactly understanding of those it rules over) just to have it fly around the galaxy on the off-chance of finding some capital ships to blast away? It's not the most manoeuvrable or subtle craft. Destroying planets, or at least having the ability to destroy planets, is all part of its purpose; it is a weapon of fear to keep systems from defying the oppression of the Empire. The fact that both Death Stars were defeated before they got a chance to be properly used (Alderaan excluded) doesn't mean that they were never going to be used!
The point of the rebels wanting to blow both Death Star's up isn't just one of self defence, but also of necessity in their crusade to defeat the Empire and bring freedom back to the galaxy.