Preheat the oven to 375º F.
Spread chopped sweet potatoes on a baking sheet with 1 teaspoon of oil. Toss and then roast for about 20-30 minutes or until tender. Note: you can also steam the sweet potatoes if you’d like!
While the potatoes are roasting, set a steamer basket insert into a large saucepan and fill with water just below the steamer. Bring to a boil. Add green beans and asparagus, and steam for approximately 5 minutes (or until desired level of tenderness). Let all the veggies cool.
Make the dressing by whisking together all the ingredients in a small bowl or glass jar.
For a mason jar: Add 2-3 Tablespoons of dressing into a large, wide-mouth mason jar, then start layering ingredients in this order: olives, green beans, asparagus, sweet potatoes, tomatoes, canned tuna, arugula, hard-boiled egg, dill.
For a meal prep container: Line bottom of container with arugula and layer all ingredients in columns/sections on top. Store dressing in a separate container.