Crunchy carrot salad

Name: Crunchy carrot salad
Prep time: 5 min
Cook time: 10 min
Total time: 15 min
Cuisine: European, British
Ingredients: ½ orange, zest only, no white pith; 6 sprigs fresh flat-leaf parsley, leaves only; 30 g orange juice (approx. 1 orange); 450 g carrots (approx. 4), peeled and cut into thirds; 250 g green apple, cut into quarters and cores removed; 2 celery stalks (approx. 120 g), cut into halves; 1 pinch sea salt (optional); 60 g walnuts, chopped (optional); 1 tbsp olive oil (optional)