Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Wash potatoes thoroughly and cut in half with skin. Mix in a bowl with sea salt and 5 tablespoons of oil. Place on a baking tray and bake in a hot oven for 35-40 minutes.
For the pesto, roast pine nuts in a pan without fat, remove and let them cool down. Grate the parmesan. Peel and roughly chop the garlic. Wash basil, shake dry, pluck leaves.
Sort the arugula, wash and drain well. Process basil, half rocket, pine nuts, parmesan, garlic and 150 ml oil to pesto in a universal chopper or with a hand blender. Season to taste with vinegar, salt and pepper.
Take the potatoes out of the oven and let them cool down. Wash and halve the tomatoes. Mix potatoes, tomatoes and pesto. Leave to stand for about 1 hour. Add the rest of the rocket salad and season to taste again.