On the second map, fast travel to the Northwest encampment in the Cape of Nurn. Jump North off the platform and head West and North around the massive rock. Use Wraith Vision
to see the first archer directly North of you on a ledge, use
Shadow Strike to teleport behind the archer and stun him, then hold
to Dominate. Gain Intel and kill or dismiss the archer. Use Wraith Vision again and see if there is an archer either directly West of you or to the North-NorthWest. Shadow Strike and dominate them as well.
To quickly boost this, highlight the same fast travel location and advance time. This will reset the archers and refill your arrows so you can Shadow Strike. See my video for a demo of this technique.
EDIT: I've added a video below to show how to get 2 dominations per minute via my method. In my first run the second archer is West of me and in the next run the second archer is North-NorthWest. Sometimes all three archers are available as targets
If you're using the new TA App and want to unlock achievements in that simultaneously, have this solution pinned while you complete the challenge and you'll unlock:
EDIT 2: If you haven't played the mission to enhance your dagger called "Clear the Skies," Devious Jedi
notes that this mission supplies you with an infinite number of archers. This mission requires you to stealth kill 10 archers without raising an alarm; if you dominate them it doesn't count towards the mission and they continuously respawn, and they are clearly marked on the map and clustered together for your convenience.