Prawn tempura with mango salad & spicy chilli dressing

Name: Prawn tempura with mango salad & spicy chilli dressing
Prep time: 30 min
Cook time: 35 min
Total time: 35 min
Yield: 4 portions
Ingredients: 150 g Kewpie mayonnaise; ½ tsp sesame oil; 1 tsp shichimi togarashi powder; 20 g rice wine vinegar; 2 tsp mirin; 2 pinches sea salt; 2 baby cos lettuce; 1 - 2 ripe mangoes; ½ red onion; ½ cucumber; vegetable oil; sea salt; 20 large raw prawns; 30 g cornflour; 1 egg; 200 g ice cold water; 100 g sparkling mineral water; 150 g plain flour; 1 tbsp sesame seeds