Columbia Harbour House and the Plaza Restaurant have great salads with grilled chicken, feta or bleu cheese, nuts, and fruit (ie, pears, mandarin oranges). These have changed slightly over the years, so I don't know exactly what the ingredients are now.
The Plaza is table-service and a very relaxing, air conditioned place to have great sandwiches, ice cream, soup, and salad. Definitely a step up from counter service, without having to pay for an entire buffet or more costly meal.
I also loved the salad with grilled steak for lunch at the Kona Cafe at the Poly.