Add potatoes to a pot and cover with cold water by at least 2 inches. Add a pinch of salt. Bring to a boil over medium high heat. Boil potatoes for 10-15 minutes or until fork tender. Once cooked through, remove potatoes from the boiling water with a slotted spoon and rinse in cold water.

Add green beans to the boiling water and cook for about 5 minutes (or until desired level of tenderness). Drain and run under cold water or place in an ice water bath.

Let all the veggies cool and once potatoes are cool enough to handle, chop in halves or quarters.

Make the dressing by whisking together all the ingredients in a small bowl or glass jar.

For the mason jars: Line up 4 32 ounce wide-mouth mason jars. Add 3 Tablespoons of dressing into each jar then start layering ingredients in this order: ½ cup potatoes, ½ cup green beans, ¼ cup tomatoes, 4 ounces tuna, 1 hard boiled egg, olives, parsley and arugula. Place lid on jars and keep in fridge until ready to serve.

When ready to enjoy, shake jar and pour into a serving bowl.