Set a steamer basket in a large pot with a lid. Fill with enough water to come just below basket; bring to a boil. Place potatoes in basket; reduce heat to a simmer. Cover pot; steam, tossing potatoes occasionally, until tender, 10 to 12 minutes.
Meanwhile, in a medium bowl, place lemon zest and juice; season with salt and pepper. Using tongs or a slotted spoon, transfer potatoes to bowl. With a rubber spatula, gently toss potatoes with lemon juice. Refrigerate until cool, at least 1 hour.
Toss herbs and oil with cooled potato mixture; season with salt and pepper. If storing, cover and refrigerate up to 1 day; bring to room temperature before serving.