cwm - would they not let you order the salad without onions?
Judging from cwm's description, the toppings sound like they were pre-mixed, perhaps even chopped together in a food processor. The onions in the photo were in rings, causing her to believe that they could be easily removed.
The correct thing to do is to ask for a manager on your way out, and politely explain the problem(s). Even if there is nothing to be done right then, the manager can make note of the complaint and pass it on. Since this is a big chain, a complaint about the way a dish is prepared can also be made to the corporate level. Of course, this is easy to say after the fact, but the corporate-level complaint could still be done.
The waiter is still at fault. He should have noticed that much of the food was not being eaten. When cwm and her boyfriend refused to-go boxes twice, he should have asked if there was a problem with the food.
As long as we are handing out faults, boyfriend get 30 lashes with a wet noodle for not noticing that the appetizer that he was ordering to share contained jalapenos.
Cwm, you have my sympathies. My best friend cannot eat peppers of any sort, and onions and garlic are severely limited. There are surprisingly few restaurants where she can count on finding a choice of things to eat. Of the big chains, we are pretty much limited to Olice Garden and Red Lobster. It's a shame because there are so many ethnic restaurants in our area, but navigating the menus are like picking her way through a minefield.