Heat the oil in a wok and fry the dried fish till lightly browned and drain on a paper towel.
Mix the lime juice, chillies, fish sauce and palm sugar together until the sugar is dissolved. Toss in the tomatoes, onion and cashews and mint. Coat everything well and then add the tiny fish and toss well. Taste the salad and adjust if needed. place the salad on the lettuce and serve.