Pour the oven fries into a roasting tray and drizzle a tablespoon of oil over the chips. Sprinkle 1 teaspoon of salt and 1 teaspoon of Cajun seasoning over the chips. With your hands, toss the chips around until the oil and seasonings evenly coat the chips.
Place the chips in the oven to cook at 180°C (gas mark 4, 350°F) for 20 to 25 minutes or until soft and starting to colour.
While the chips are cooking in the oven, with a sharp knife cut the bacon into small 1cm pieces. Chop the red pepper into small cubes and peel and dice the onion.
With a wok or frying pan add 1 tablespoon of vegetable oil and stir fry the sliced onions, bell peppers and bacon pieces and cook until the onions start to soften and the bacon is cooked (keep frying if you like them crispy).
When the chips are cooked, reheat the stir fry mixture for 1 to 2 minutes and add the cooked chips and mix together. Add the remaining teaspoon of Cajun seasoning and mix until evenly distributed.
Place the mixture in an ovenproof dish, sprinkle with chopped spring onions and top with grated cheese. Cook in the oven until the cheese has melted.