Ratchet & Clank 2: Going Commando

Go down the route that goes past the the MegaCorp vendor and then past the armour vendor. When you get to the end, you'll trigger a brief cutscene. You'll then be transported to a very small moon. It's these building's you need to destroy. The easiest way is to melee bash them. Don't worry too much about the boss, he won't be able to kill you before you're done, but might nneeda second attempt to kill him aswell.