This was a terrific dish. I used about half the spinach called for and the same amount of dressing, and that seemed to come out about right - I'd make more dressing if I were going to do a full 8 cups of spinach. I also only used 1/2 of a medium-sized red onion. In the dressing, I left out the yogurt because my dinner companion does not like it. Otherwise I followed the recipe.
I'm a little skeptical that the first step of toasting the quinoa made a difference; I plan to try again without that, just to save time. Toasting the sliced almonds definitely did make a difference, though, and they really added to the flavor of the dish.
My results might have been improved by the fact that instead of pre-ground cumin from the store, I used my personal stash of cumin, which was cumin seeds that I had toasted and ground a few months ago. It makes the cumin much more flavorful. I also used fresh lemon juice.