Whisk together buttermilk, mayonaisse, shallots, chives, lemon juice, celery salt, and a little salt and pepper in a small bowl. Cover with plastic wrap, and refrigerate until cold, about 30 minutes.
Cut lettuce lengthwise into quarters.
Transfer a wedge to each of 4 plates.
Drizzle each wedge with some dressing, and garnish with tomatoes and additional cracked black pepper.
