Prepare the Walnut Oil Vinaigrette. Cover and chill while preparing the salad.
In a large salad bowl, combine mesclun, tomatoes, onion, celery, cucumber, walnuts and cranberries. Shake the vinaigrette; pour over the mesclun mixture. Toss gently to coat. If you like, serve with cooked chicken. Makes 4 main-dish or 6 side-dish servings.
In a medium bowl, combine vinegar and shallot. Let stand for 15 minutes. Whisk in mustard, honey, salt and ground black pepper. While slowing adding walnut oil in a steady stream, whisk until mixture is thickened. Makes about 1/2 cup.