Cook the pasta according to package directions until al dente.
In a large skillet, heat the olive oil over medium heat.
Add the diced onion and bell pepper to the skillet, and sauté for about 5 minutes until softened.
Stir in the minced garlic and cook for an additional minute.
Pour in the diced tomatoes and coconut milk, stirring to combine.
Add the Cajun seasoning, then simmer on low heat for 5-10 minutes.
Toss in the cooked pasta and spinach, stirring until the spinach wilts and everything is heated through.
Season with salt and pepper to taste before serving.