Salad in a jar - I don't put any dressing in the jar. If you do make sure its no where near the lettuce. I reccomend not putting the dressing in the jar at all. Your salads will last a little over a week w/o dressing!
Lunch in Mason Jars- lots of recipes for mason jar lunches. The jars help keep the food fresh so you can make a week's worth of food ahead of time. Would be great for beach lunches, don't have to touch my food after baiting my hook