This is a "Salad as Big as My Head!" One of my strategies for eating low calorie/high protein is to fill up on the veggies and meat. Here's my recipe for a very filling salad for around 400 calories.
1/2c. sliced mushrooms
1/2c. raw broccoli
6oz. cooked chicken breast
1/2c. lowfat cottage cheese
You probably noticed there's no dressing, croutons, crackers, nuts, or cheese on this salad. Yep, that would be more fun, but the calories would jump real fast. The cottage cheese provides enough moisture to trick you into thinking there's dressing.
This salad can be easily put together in the morning and taken to work. Just keep the chicken and veggies separate from the cottage cheese to avoid limp spinach.