In a heavy skillet, fry the chorizo in oil over medium heat. When just browned, add the onion, garlic, and rice and saute briefly until the rice is translucent. Pour in the stock, soy sauce, vinegar, add the bay leaf, and bring to a boil over high heat. Reduce the heat to low, cover, and simmer for 15 to 18 minutes until most of the liquid is absorbed. Stir in the cooked shrimp, avocado, and pureed tomatillos, cover again, and continue cooking for 2 more minutes. Remove the pan from the heat and let the rice steam, covered, for at least 10 minutes. Stir and serve.