Bring a pot of salted water to a boil. Add the asparagus and blanch for 2-3 minutes until bright green and tender-crisp. Drain and immediately transfer to a bowl of ice water to stop the cooking process. Let it cool for about 5 minutes, then drain again and pat dry.
In a large bowl, combine the blanched asparagus, cherry tomatoes, walnuts, and grated Parmesan cheese.
In a small bowl, whisk together the olive oil, lemon juice, Dijon mustard, salt, and pepper until well combined.
Pour the dressing over the salad and toss gently to coat all the ingredients evenly.
Serve immediately or chill in the refrigerator for about 30 minutes to allow the flavors to meld before serving.