Pit the avocados and scoop out the flesh. Place the avocado, coconut water, lime juice, cilantro, 1/2 cup chives, shallots, and cayenne pepper in the blender or food processor. Process until smooth. Add additional coconut water as needed to achieve a soup-like consistency. Add sea salt to taste. Chill until ready to serve. Spoon in glasses or bowls, and garnish with chopped walnuts and chive pieces.