Garnish: 1 bunch cilantro, juice from 2 limes, Siracha hot sauce
Heat the oil in a large soup pot. Sautee the onion and cauliflower on medium heat for 7 minutes, stirring frequently.
Add the broth, tomatoes, and garlic. Bring to a boil and then turn the heat to low. Allow the soup to simmer for 15 minutes. Add the zucchini and salt and simmer for 5 more minutes or until the zucchini and cauliflower are soft. Remove the pot from the heat.
Pour the coconut milk into a high-powered blender and add about 3 cups of the soup (mostly cauliflower if possible). Puree the soup and coconut milk until it becomes creamy (be careful because the soup is very hot). Pour the puree back into the soup pot.