Heat the oil in a medium pot with a tight fitting lid. Stir in onions and cook for 5 to 7 minutes.
Add cayenne and cumin and cook an additional 2 minutes. Add rice, then stir in tomatoes and 2 cups of water. Season with salt and pepper and bring to a boil. Then turn down to a simmer, cover and cook for 20 minutes.
In the last 2 minutes of cooking add the peas. Turn off the heat and allow to sit, covered, for 5 minutes. Fluff and serve.