Heat oil in Dutch oven or any large covered pot. Sauté the Onion and garlic for a few minutes. Add the Chicken and continue to cook and stir until the Chicken is nearly done. Reduce heat. Add tomatoes and ginger and stir for a few minutes.
Add coconut milk and simmer over low heat until Chicken is fully cooked and sauce is thickened. Stir often. Serve over rice.