1. Place sugar in a small, heavy saucepan over medium-high heat; cook until sugar dissolves, stirring gently as needed to dissolve sugar evenly (about 1 minute). Continue cooking 1 minute or until golden (do not stir). Remove from heat; carefully stir in nuts to coat evenly. Spread nuts on a baking sheet coated with cooking spray; separate nuts quickly. Sprinkle with 1/4 teaspoon salt. Set aside until cool; break into small pieces.
2. Combine vinegar and mustard, stirring with a whisk. Gradually add oil, stirring constantly with a whisk. Stir in capers.
3. Combine lettuces and radicchio; top with pear and candied walnuts. Drizzle dressing evenly over salad; sprinkle with remaining 1/4 teaspoon salt and pepper. Toss gently to combine.
Wine note: I favor a crisp white with almost any green salad, and Candied Walnut, Pear, and Leafy Green Salad is no exception. 2007 Pinon Vouvray Cuvée Tradition ($16) has a gorgeous nose of honey and lemon peel that resonates perfectly with the candied nuts and pears. --Gary Vaynerchuck