Toast walnuts for salad and dressing. Preheat oven to 350°F. Place nuts in single layer on baking sheet and roast 7 to 9 minutes. Allow to cool. Rub nuts with hands or in cotton towel to remove as much brown skin as possible.
To make dressing, in a food processor finely chop 1/3 cup toasted walnuts. Add 2 tablespoons water, lemon juice, mustard, honey, oil, salt and pepper. Blend until creamy. If dressing is too thick, adjust by adding a small amount of water at a time, not more than 3 tablespoons total.
In a serving bowl, combine lettuce, radicchio, frisee, and endive. Toss with dressing.
Quarter and core apple, leaving skin on, and slice very thin into small bowl. Toss with small amount of lemon juice to prevent browning. Add apple slices to salad. Top salad with crumbled goat cheese and chopped toasted walnuts. Serve immediately.