Place the potatoes in a large pot and cover with cold water by one inch. Add a pinch of salt. Bring to a boil then reduce heat and cook about 15 minutes. 

While potatoes boil, place asparagus in a single layer on a baking sheet. Drizzle with olive oil, salt and pepper. Broil until slightly charred. Let cool and cut on the bias into about one inch pieces.

When the potatoes have about 3 more minutes to cook, add peas.

When potatoes are fork tender, strain potatoes and peas together.

When potatoes are cool enough to handle, slice them in half. Then combine potatoes, peas, asparagus and mint in a large serving bowl. 

Combine all ingredients for the dressing EXCEPT the oil and whisk well. 

Slowly add the oil while whisking continuously until dressing emulsifies.

Adjust salt and pepper to suit your taste.

Pour over prepared salad and serve.