The original idea was to have this on fish tacos, but I went the fake meat route instead. (The fake chicken things are a bit weird on their own, but I've found quite a few good uses for them by slicing them and putting them in things.) This makes a lot though, so you should eat a bunch of salad on its own too.
1/4 c lime juice from 2 limes
1 red onion, thinly sliced
1/2 head green cabbage, thinly sliced
1 yellow pepper, thinly sliced
1/2 c cilantro leaves, coarsely chopped
salt and chile powder to taste
1 avocado, thinly sliced
Toss the red onions with the lime juice in a large bowl, and let sit and mellow together while you chop the rest of the veggies. Add everything except the avocado to the bowl and toss well to combine. Add the avocado and toss gently.