Despite the trophy description, this can also be done on the bonus mission "Landslide".
A very easy way to do this is to follow the "Cheat Sheet" Mission Story. Following the in-game guide, you'll have to interact with a laptop, easy enough to quickly jump down the ledge when nobody's looking.
Then you gotta go into an apartment and tell the target to go somewhere through a microphone. You can just wait for the assistant and his bodyguard to leave the building, then quickly walk in through the open door. This way you don't have to lockpick out in the open.
Sneak back out and onto the graveyard and wait. I hid at the little beach with the trash on it to be safe. The target will lean against a handrail, allowing you to push him into the ocean. Sneak out, and escape. A lot easier than on the other two missions in my opinion.