Melt coconut oil in a large soup pot over medium heat. Add salt and leeks and sauté for 5 minutes. Add garlic, ginger and cauliflower and sauté for another 5 minutes. Add cashews and broth. Bring to a boil, reduce heat, cover and simmer for 30 minutes.Remove from heat and let cool for an hour or longer. Puree in a high speed blender until creamy.Season with vinegar or lemon juice, and salt to taste.Serve with hot sauce if desired.