Bring a large stockpot filled with salted water to a boil over high heat. Prepare an ice-water bath and set aside.
Add the asparagus to boiling water and cook until just tender, about 5 minutes, depending on thickness. Drain and transfer to ice-water bath for 5 minutes. Drain well and transfer to shallow serving platter or long serving dish.
Meanwhile, in a small bowl, whisk together the oil and vinegar. Stir in the tomatoes, scallions, parsley, salt and pepper.
Add the sauce to the asparagus, tossing gently to combine. Serve at room temperature.