Here's the situation: I ended up using a regular old white onion, as the red onions at the store that day were way too huge for my purposes. I used garlic from a jar rather than a fresh clove thanks to a bad experience with garlic earlier this year. And I omitted the lemon zest, since I didn't have a whole lemon on hand, which meant that I also used bottled lemon juice rather than just-squeezed. But all in all, the final product was absolutely delicious, and in fact (as the Cilantropist notes), the longer it sat, the better it tasted. And it was good at room temperature as well as chilled.
I recommend this versatile salad as a good late-summer side dish. It also goes very well with the tuna sandwich I wrote about last week!
Photo via here.