To make the dressing, whizz together the garlic, chilli and sugar in a food processor to make a rough paste. Add the fish sauce and lime juice, then season to taste.
Fry the shallots in the oil for around 5 mins or until they are crisp and golden brown. Then remove with a slotted spoon and drain on kitchen paper. Toss the apple in the lime juice, then mix with the tomatoes and dressing. Spoon onto plates and top with the peanuts, crisp shallots and coriander.