Meal prep for office with minimal cleanup?

My office does have a kitchen with provided dishwash soap, but I personally follow my break pretty strictly and won't have to spend time having to clean my container, eg after eating tomato pasta or salad with dressing. Some things I can think of is a BL (no tomato as bread will become soggy especially after awhile since prep) or PB sandwich to prep on Sunday. What other foods I should consider prepping?