You don't get much more compact that this. Winner of a Good Design Award, the Raymay Pencut Scissors are a fold-up blade that can slip into your pen case just like any other pen or pencil. They work using a special slider and separation switch, so they are complete safe to store.
When you need to cut something up, just pop out your Pencut, slide it open and use the "handle loop" for extra grip. It's no secret that Japan takes its stationery very serious and so even the Pencut comes in a range of colors (blue, black, green, pink or white) for any taste. The blade is also double-edged so can be used whether you are left- or right-handed.
The Raymay Pencut Scissors features: