Preheat oven to 400 degrees F.
Add potatoes to a parchment paper-lined rimmed baking sheet and season with salt and pepper. Toss with 2 tbsp of olive oil. Spread potatoes evenly on the pan.
Roast for about 35 min. Remove pan from oven.
Add arugula to potatoes on pan; mix to combine. Return pan to oven for 2 min to slightly wilt the arugula.
Transfer to a serving platter.