Preheat oven to 400°F.
Scrub potatoes and cut into bite-sized chunks, roughly one inch wide. Toss with a drizzle of olive oil and season with salt and pepper, then spread in an even layer on a baking sheet lined with aluminum foil. Roast for around 30 minutes, until golden brown and tender.
Meanwhile, toss asparagus with another drizzle of olive oil and season lightly with salt and pepper. Add to the oven with the potatoes during the last 8-10 minutes of cooking.
Prepare Dijon yogurt dressing by adding the yogurt, Dijon, red wine vinegar, shallot, salt, and pepper to a small bowl and whisking until smooth. Taste and adjust amounts to your liking if necessary.
Remove asparagus and potatoes from oven and let cool slightly. Transfer to a large bowl and mix with the Dijon yogurt dressing. Serve warm.