During chapter six, the first giant spirit monster can be skipped by using Korra's tornadoes with proper timing and luck. What I do to get this 60% of the time is attack the enemies from left to right until they're all stunned, then take 3-4 steps toward the barrier facing the start of the level and start healing the spirits. I line myself up with the middle of the barrier and when I'm about five feet away from it, perform a light air bending combo. The giant spirit should spawn towards the middle or end of my combo. If I get lucky, the enemy will be dead when the spawn animation is over. Contrary to previous beliefs, I discovered that you can do this with Hundun as well. After you knock him down while he's on his platforms, run to the center of the field and attack with a light air combo again. It's much less consistent with him, though.