Heat olive oil in a large non-stick skillet. When the oil is hot, add sliced sausage and cook until sausage is nicely browned about 3-4 minutes; remove from pan.
Add a bit more oil to the same pan and add the onion; season well with salt and pepper. Cook for 1-2 minutes, then add bell peppers. Cook for about 3-4 minutes until veggies are slightly softened.
Stir in diced tomatoes, Cajun seasoning, tomato paste, and cooked sausage.
Give everything a big stir and cook a few minutes longer. Add a little water or chicken stock if the liquid evaporates too quickly. Serve on soft hogie rolls or over rice or pasta!