Clean (brush) the potatoes well and cut them with the skin into bite-sized pieces. Roast in oil at 225 °C in the oven until they are crispy and cooked, approx. 20-30 minutes. Season with salt and pepper.
Grill the bell peppers, chillies and the garlic bulb whole until the skin turns black and sooty. Place in a freezer bag and wait ten minutes, then peel the peel, remove the stalks and seeds.
Pull out the garlic cloves. Puree the vegetables with mayonnaise, cumin and paprika powder. Season to taste with salt.
Mix the potatoes with the dressing and turn in chopped spring onions. Sprinkle with chopped parsley, coriander and watercress. Pour lime juice over it and serve.