Place a large Dutch oven over medium heat and add the oil and bacon. Cook, stirring, until the bacon is crispy and golden and the fat has rendered, 4 to 5 minutes. Add the onions, green peppers, red peppers, rice and salt; cook, stirring, for 5 minutes, until the onion is soft and the rice is lightly toasted. Add the tomato paste and cook for 2 to 3 minutes, stirring. Add the oregano, cumin, pigeon peas, tomatoes, chicken stock and 1 cup water. Bring to a boil, then reduce the heat to a simmer. Cover with a lid and cook until the rice is tender, 25 to 30 minutes.
Remove the lid and fluff the rice with a fork. Garnish with cilantro and scallions.