Using a pestle and mortar, spice grinder or food processor, crush all the dressing ingredients, except for the lime and fish sauce, together until you have a thick paste. Season with salt, then squeeze in the lime juice and stir in the fish sauce. You want it to be the consistency of double cream, so add a dash of water if it’s too thick.
Wash the vegetables and slice them all (except the peas!) very finely. Place in a bowl, scatter over the brown shrimps and toss with the dressing. Have a taste and add a little extra salt or lime juice if necessary. Sprinkle with a few coriander leaves, then serve.