Preheat the oven to 220°C.
Peel and dice the potatoes into 1.5cm cubes.
Toss potatoes in a bowl with two tablespoons of olive oil.
Roast potatoes on a baking tray for 50 minutes until golden.
Spatchcock the chickens by removing the backbone and flattening the breastbone.
Place chicken in a baking dish, rub with olive oil and season.
Roast chicken in the oven for 25 to 30 minutes until golden.
Peel the oranges by cutting away skin and pith with a knife.
Slice the oranges widthways into 5mm slices.
Arrange orange slices, sliced onion, and watercress on a plate.
Drizzle the salad with olive oil and season with salt and pepper.
Rest the cooked chicken for five minutes before serving.
Whisk tomato paste, vinegar, paprika, Tabasco, salt, and remaining oil.
Toss the roasted potatoes in the spicy dressing.
Serve the chicken with potatoes and orange salad.