Heat the coconut oil in a large stockpot or Dutch oven over medium-high heat. Add the onion and a pinch of salt and sauté until golden. Push the onions to the sides of the pot and add the Brussels sprouts in a single layer (or as close to a single layer as possible). Allow them to sear, stirring only occasionally. Stir in the ginger, garlic, and crushed red pepper flakes. Cook 1 minute, until fragrant. Add the rutabaga, carrots, and vegetable broth. Cover, and bring to a boil. Lower the heat to a simmer and stir in the chickpeas and lime zest. Cook, partially covered, stirring occasionally, for 5-10 more minutes, until the rutabaga is tender. Stir in the coconut milk and lime juice and cook an additional minute, until heated through. Taste and add more salt if needed.