In a wok or large skillet, heat 2 tablespoons of canola oil over medium-low heat for 2 minutes. Add the sausage and render the fat, about 5 minutes. Using a slotted spoon, remove the sausage on a paper towel lined plate and set aside.
Increase the heat to medium and add the celery, onion and bell pepper. Stir to combine and let cook until softened, about 3 minutes.
Add the remaining 1 tablespoon of canola oil to the wok and increase the heat to medium-high and let the pan get hot, about 1 minute. Add the cooked rice, shrimp and Cajun seasoning, stir to combine. Let the rice fry and shrimp cook while stirring often, until the rice is golden and crispy, about 8 to 10 minutes. With four minutes left in the 8 to 10 minutes of frying, add garlic, sausage and crab to the rice. Stir and continue to cook for the remaining 4 minutes.
Add the stock and vinegar to the rice. Stir to combine and deglaze the pan. If the rice looks dry, add 1/4 cup more of stock. Stir, taste and salt to preference. Scoop the rice into serving bowls. Top with green onions and optional hot sauce. Serve warm.