Dice the onion, core and peel the chilli pepper and finely chop a piece of it - amount according to personal taste and the spiciness of the pod. Mix well all ingredients for the dressing in a bowl.
Peel the mango, cut from the stone and cut the pulp into approx. 1 - 1.5 cm cubes. Core the tomatoes and dice the pulp.
Mix both with the dressing and let it steep for about 2 hours. Stir in between and season to taste.