Kunkka is very good ganker and as such, should almost always be played as position 2 on the farm priority, at the point you get your shadow blade + crystalys you can kill most squishy supports with 1 shadow blade hit, you should use it to your favor and start roaming for ganks as soon as you get these items up.

Make sure to abuse of tidebringer, and combo it with shadow blade, with some lucky crits you can net some rampages. So, pick your sword, get a bottle of rum and be ready to kill some tidehunter!