Using Mason jars is an easy way to make up salads to take to work or to have handy in the fridge for lunch. Jamie Oliver calls them jam jar salads.
The main process is putting it in the correct order.
1. Salad dressing
2. Grain or protein
3. Nuts and cheese
4. Leafy greens
Here are a few sites to give you some ideas:
Buzzfeed - Mason jar salads
How to pack the perfect salad in a jar
Mason Jar Salad Recipes
Note: FarmersFridge.com has other jar recipes too.