To prepare salad, preheat broiler. Cut peppers in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 5 minutes. Peel and chop peppers.
Combine peppers, turkey, spinach, and lettuce in a large bowl.
To prepare vinaigrette, cook the pancetta in a skillet over medium-high heat until crisp. Remove pancetta from pan; chop and set aside. Reserve 1 tablespoon of drippings in pan. Add shallots and garlic to pan, and sauté for 1 minute or until tender. Stir in the cranberry sauce, vinegar, olive oil, salt, and pepper. Cook over medium-low heat 2 minutes or until warm. Pour warm vinaigrette over the salad; toss. Top with pancetta. Serve immediately.