What the achievement asks
Find enlightenment by cleaning the streets of Undermine, which means kicking twenty-five cans. Ten points, account-wide.
You can kick the same can over and over
This is the whole achievement, and it turns a scavenger hunt into a minute of clicking. One can counts repeatedly. Players report getting five ticks from a single can by clicking it again and again.
So you do not need twenty-five cans. You need one can and some patience, and any can you happen to be standing next to will do.
Finding a can at all
The cans are small, green or brown, and they blend into the street. They are genuinely everywhere in Undermine: on the roads, down the side alleys, around the buildings.
Lower Ground Clutter to 1 in the graphics settings. It strips out the scenery that hides them and they stand out immediately.
Get off the D.R.I.V.E. vehicle. The cans are too small to pick out at that speed and height. On foot, or on an ordinary ground mount, five minutes of wandering turns up several.
Some cans have a sparkle animation and some do not. The plain ones work exactly the same, so do not walk past them looking for a shinier one.
Where it fits
One of six under Going Goblin Mode, which rewards the Gallagio Grand Gallery warband campsite and is part of Worldsoul-Searching, the War Within meta. It is the shortest of the six by a wide margin, so clear it on your first walk through the city.