Yeah, I can't figure out how to throw sand either. And I'm too lazy to climb to the high shelf where I dropped the humongous fucking LE box.
As to the assassination of the dude in the tunnel guarded on both ends, just equip your money pouch like a weapon and start tossing your gold like mad. In the ensuing guard/civilian clusterfuck, just walk up to the dude shaded in gold (eagle vision), and shiv him in the back. Mission accomplished. No need to wait for the smoke bomb upgrade or involve courtesans or hired thugs.
Speaking of assassinations. WTF. I start Memory Sequence 5, and it's like I have an infinite number of these assassinations to do in Florence. I did 6 in a row last night, and the 3 Assassination Markers on my map/GPS are STILL there!? They're all uniquely named and logged in the DNA strand, but do they ever end?
WTF happened to the spacing out of missions there? Courier and Beat Up missions, by comparison, are far fewer and further apart.