In a pot, heat achiote oil over a medium heat and add the longaniza. Cook the longaniza until it's dark and crispy, or about 4-5 minutes.
Add the bell peppers, garlic, sofrito, tomato paste, adobo, and salt to the pot and mix until the vegetables are beginning to soften and the spices are fragrant, or about 2 minutes.
Add the water to the pot and wait about 1-2 minutes until it starts boiling. Add the rice and stir occasionally until almost all the water has evaporated.
Add the shrimp and green peas to the pot and give it one last mix before creating a dome with the rice and covering with a lid. Lower the heat to simmer and cook for 15 minutes.
Remove from heat, fluff with a fork, cover, and let sit for 5 minutes before serving. ¡Buen provecho!