In a heavy-bottomed saucepan over medium-low heat, warm the oil. Add the onion, garlic, ginger and chili and cook, stirring occasionally, until the onion is translucent, about 4 minutes.
Stir in the curry powder and cook, stirring constantly, until fragrant, about 30 seconds. Season with salt and pepper.
Add the sweet potato, chickpeas, coconut milk and water to the pan. Raise the heat to medium-high, bring just to a boil, reduce the heat and simmer, uncovered, until the sweet potato is tender, about 10 minutes.
Add the peas and tomatoes and cook until heated through.