Whisk yogurt together in a small bowl with the lemon zest, juice and brown sugar.
Combine pears, grapes, celery, cranberries, pecans and chives in a bowl. Toss gently to combine with the dressing. Season, to taste, with salt and pepper.
Lay lettuce leaves on a work surface, dull side up. Divide mixture evenly between the centers of each of the lettuce leaves. Fold the stems and tops inward and roll tightly from one side to form cone-shaped wraps. Use toothpicks to hold wraps together, or roll with parchment paper.