For the blue cheese mayonnaise, combine the cheese and mayonnaise in a small bowl, and mix well. For the avocado puree, mix the avocado puree, salt and pepper, and lemon juice until well-blended. To assemble the sandwiches, spread one bread slice with 1 to 2 tablespoons of the blue cheese mayonnaise. Layer the mixed greens, 2 tomato slices, 2-oz. smoked turkey, and 2 bacon strips on the bread. Spread another slice of bread with the avocado puree, and top the other half of the sandwich. Repeat, using all ingredients.