Here is my 100% Achievement video guide for Elea!
For this particular achievement, As soon as you get into chapter 3 on the spaceship, you will get up from the VR chair, turn right and go onto the Mars sim..
You spawn in a tree area, infront of you is a red origami swan, on a pointed rock is a white origami swan... Hit the red into white and achievement pops.
Go to 53:30 to see how to get this!
Good shout by PhillipWendell, you don't actually have to restart if you miss the swan or it falls on the floor! It's just rather hard to find thats all, so no need for a restart, just keep searching!
Also, to aim, use RT and then LT to shoot, make sure you aim JUST LEFT of the swan to hit it, doing it straight on will make you miss
Hope it helps