Transfer the pasta to a large bowl. Add the broccoli, snow peas, bell pepper, and scallions; toss. Add the vinaigrette and toss again. Taste and adjust the seasoning.

Advance preparation

This salad will keep for up to 3 days in a covered container in the refrigerator. (It's best to refrigerate the dressing and salad separately; toss together up to 1 hour before serving.)