Quarter the tomatoes and then cut into very thin slices. Peel the onions, quarter them and also cut them thinly. Put both in a salad bowl. Mix the vinegar and sugar with the finely chopped chilli sauce and the chopped coriander. Pour over the tomatoes and onions and leave to stand in the fridge for about an hour, covered.
Roast the chopped garlic and peanuts together in a pan (if possible without fat). Set aside to add to the salad just before serving. Possibly drizzle a little sesame oil over the salad.
With us this is a big hit at potluck evenings, barbecues or as a starter. If there is anything left over, it will still taste great the day after.