Take a mortar and pestle and pound the garlic and the chilies until they come to a paste. Add the shrimp (if using) and the green beans and pound them just a little so you squash them without turning them into a paste. Add the carrot and then the papaya and continue to pound away, this will bruise the papaya so it can take on the flavour of the chilli and garlic.
Now add the lime juice, fish sauce and palm sugar and take a spoon and stir the ingredients through so the flavours are even throughout.
Have a taste, the flavour should be hot, sour and salty, if you feel the flavour is uneven add a little more lime juice or fish sauce or chili to balance it out.
Finally fold through the mango, halved cherry tomatoes and the chopped peanuts, stir once more and serve immediately.
