>>2012158
>I know you can destroy some structures and they get knocked out of them, but I couldn't find any
On USJ, Civilians have a random chance (40%, I think) of spawning when you destroy buildings or houses in Landslide Zone or Collapse Zone (East and Northeast side of the map,) but on all maps they'll also spawn from those blue booths that spawn around the map.
There are some static civ spawns around the map as well where you don't need to destroy anything, they're just there on the ground.

There's no real tech to it besides knowing where the static civ spawns are and where the booths spawn so you can head directly there instead of searching aimlessly.