Place the walnuts in a small saute pan with the sherry and sugar. Cook over high in heat, stirring constantly with a wooden spoon until the sherry and sugar caramelize on the walnuts. Set aside to cool.
To make dressing, mix the olive oil, balsamic vinegar, champagne, mustard, and sea salt in a mixing bowl until smooth and creamy.
Place the lettuces into the bowl, top with the mango and pear, drizzle with about 1/2 of the dressing, and toss. Then add avocado slices, crumbled pieces of blue cheese, candied walnuts, and pomegranate seeds.
Drizzle the remaining dressing and serve immediately.