I like the Jimmy Dean D-light sandwiches - my current freezer is full of the english muffin/turkey sausage kind. You only need to heat them up for 90 seconds and they're ready.
Did you ever think of packing lunches ahead of time and bringing your own? Personally, salads do not fill me up. I prefer to have something "heavier" like chili with ground turkey, and then I have cut up veggies/fruits as snacks during the day.
I'm a student as well (I also work full time) so a lot of the time dinner is just a quick egg-white omelette with spinach, pico de gallo (purchased at the grocery store) and laughing cow cheese. It takes about 5 minutes to make, and is very filling.
Sometimes I also have chicken breast and frozen veggies - heated up in one of those micro-wave steamer bags. Also filling and healthy