To prepare walnuts:
Preheat oven to 400°F
Line a small baking pan with parchment paper or foil; coat with cooking spray and set aside.
In a small bowl, toss walnuts with water.
Sprinkle with brown sugar and salt and toss to coat.
Transfer to the prepared pan.
Bake at 400 until the sugar is melted and the nuts are barely starting to brown, 6 to 8 minutes.
Cool in the pan until the sugar hardens, about 6 minutes.
To prepare Grape Salad:
Combine sour cream, cream cheese, honey and vanilla in a food processor and puree until smooth and creamy.
Transfer to a large bowl and add grapes. Stir gently to combine.
Transfer to a serving dish.
Crumble the candied walnuts on top of the salad just before serving.