I ate this almost everyday in Thailand & picked up the recipe from a cookery school in Chiang Mai.
It's definitely the best salad your likely to come across.
The key to this dish is to use lots of chili, your nose should be running & yours eye's watering!!
If you can't find green papaya you can use cucumber or unripe mango.
100g Grated papaya
1 chopped tomato
5 green beans, chopped into 1 inch pieces
A handle of roasted peanuts
2 tbsp fish sauce
2 tbsp lime juice
1 tbsp palm sugar
1 birds-eye chili
Put the chili and peanuts into a pestle and mortar and pound together.
Add the palm sugar, fish sauce and lime juice and pound until the sugar has nearly dissolved.
Add papaya and tomatoes and mix well.