Transfer the farfalle to a large bowl. Add the chicken, tomatoes, and green onions; toss. Add the vinaigrette and toss again. Taste and adjust the seasoning.

Serve the chicken salad atop the lettuce leaves arranged on individual salad plates.

Advance preparation

The vinaigrette will keep in a tightly covered container in the refrigerator for up to 2 days. The completed salad can be made early the day it is to be served; allow it to come to room temperature and assemble the plates with the lettuce leaves just before serving.