In a large pot, heat the olive oil on medium-high heat. Saute the onion until translucent, 5 to 6 minutes. Season with salt and add the garlic and let cook an additional 2 minutes.
Add all the spices, salt and pepper and mix for another minute to warm through. Add the diced tomatoes, tomato sauce and bring to a boil. Add sweet potatoes, cover and let simmer 20 to 30 minutes until cooked through and flavors have blended.
Swirl in the coconut milk and let cook an additional 10 minutes. Remove from heat and serve warm over rice topped with cilantro and mint.