Heat the oil in a medium skillet over medium high heat. Add the onion and sautee until softened, about 5 minutes.
Add the curry powder, turmeric, cumin, ginger, and garlic and cook for about 1 minute.
Remove the onions form the heat and scrape them and all the spices into the slow cooker. Add the salt, chickpeas, sweet potatoes, cauliflower, diced tomatoes, coconut milk, and enough water or broth to just cover vegetables, cover and cook on high for 4-4.5 hours, until vegetables are tender enough for your liking.
Taste and season with extra salt and pepper if desired, and serve with rice and/or naan bread.