Boil a large pot of salted water and cook linguine pasta according to package directions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Add sliced smoked beef sausage and cook until browned, about 5 minutes. Remove and set aside.
In the same skillet, add shrimp seasoned with 1 tablespoon of Cajun seasoning. Sauté for 2 to 3 minutes until pink, then remove and set aside with the sausage.
Lower heat to medium and add diced bell peppers and minced garlic to the skillet. Sauté until tender, about 4 minutes.
Pour in the heavy cream and the remaining 1 tablespoon of Cajun seasoning. Simmer for 3 to 4 minutes until the sauce slightly thickens. Stir in grated Parmesan cheese.
Return the cooked beef sausage and shrimp to the skillet. Add the cooked linguine and toss thoroughly until the pasta is fully coated in the spicy sauce. Garnish with chopped green onions before serving.