Heat the coconut oil in a large stock pot over medium-high heat. Add the yellow onion and sauté, stirring occasionally, until translucent, about 8 minutes. Add the garlic, ginger, cauliflower, curry powder, sea salt, and red pepper flakes. Cook, stirring occasionally, until very fragrant, about 5 minutes. Add the peppers and carrots, cover, and continue cooking, stirring occasionally, until vegetables have softened but are still slightly al dente, about 5 to 8 minutes.

Pour in the coconut milk, vegetable broth, lime juice, and pure maple syrup. Cover and heat to a gentle boil, then immediately reduce the heat to a simmer. Continue cooking, covered, until vegetables have reached desired done-ness, about 5 to 10 minutes.

Taste the soup for flavor. Add more sea salt, lime juice, and/or red pepper flakes to taste. Serve with fresh green onion.