In a small mixing bowl, combine the mustard, garlic, and vinegar. Slowly whisk in the olive oil until mixture thickens. Add the mustard seeds and season to taste.
In a small skillet over low heat, saute the onion in olive oil until softened. In a large mixing bowl, combine the sauteed onion, drained white beans and smoked turkey. Combine with enough vinaigrette to thoroughly coat. Place the bean and turkey mixture on a bed of lettuce and top with shavings of Parmesan or Asiago. Pass remaining vinaigrette separately. 4 servings.