Rub the pork chops with Cajun seasoning (approximately 1/2 teaspoon per side pork chop,). Allow to sit for a few minutes to let the Cajun seasoning seep into the pork chops while you prepare the onions.
Thinly slice the onions. Heat 1 tablespoon olive oil in a large skillet and saute the onions for about 5 minutes over medium heat. Remove the sauteed onions to a plate and set aside.
Heat the remaining 2 tablespoons olive oil over high heat in the same large skillet, and add the pork chops. Sear for about 5 minutes on each side. The pork chops will not be fully cooked yet.
Add in the sauteed onions and the crushed tomatoes. Top with 1.5 - 2 tablespoons Cajun seasoning and give everything a gentle stir. Season with salt and pepper (if your Cajun seasoning isn't already salty and spicy enough), or additional Cajun seasoning if you like things spicy!
Bring the tomato sauce to a gentle simmer (you'll see small bubbles in between the pork chops). Lower the heat and simmer for about 10 minutes, or until the sauce thickens a bit and the pork chops reach a temperature of 160F in the thickest part. Remove from heat and allow to rest for 5 minutes before serving.
Check the ingredients in your Cajun seasoning - some already contain salt. If yours already has salt, you can skip it from this recipe.
If you don't like things too spicy, use less Cajun seasoning, or substitute some paprika. You'll still get a delicious flavor but with less heat.