Melt coconut oil in a large soup pot over medium heat. Add salt and onion and sweat for 10 minutes, allowing the onions to color but not brown.Add cauliflower and saute for 3 minutes. Add coconut milk and broth, bring to a boil, reduce heat and simmer for 20 minutes. Remove from heat, stir in pea shoots or spinach, and allow soup to cool. Puree in a blender or with an immersion blender. Return to pot to heat. Adjust flavor with a squeeze of lemon, salt and pepper to taste.Garnish with fresh mint.