Using a large mortar and pestle, pound the garlic into a paste. Add the peanuts and chilli and pound to combine these with the garlic.Add the snake beans and gently pound, gradually adding the palm sugar, tomatoes and papaya. Continue gently pounding and mixing with a spoon at the same time.
Add the tamarind water, lime juice and fish sauce. Gently pound and mix for a further minute. Serve.