Peel and de-vein the shrimp, removing both the back vein and the white vein running on the inner crescent side of the shrimp.
Slice the shrimp into small equal-sized pieces.
Marinate the shrimp in lime juice; be sure to measure the amount of lime juice you use to marinate the shrimp.
Mix gently to ensure that all shrimp are covered with lime juice. Wait for the meat to cure and develop a white opaque color, and for the 'naam sa uh' liquids (น้ำสะเออะ) to ooze out of the shrimp meat.
When the shrimp are cooked to your liking, whether fully or semi-cooked, strain and reserve the liquids that oozed out. Seal the container with a cling film to prevent evaporation and preserve the fruitiness of the lime juice. Set aside.
Prepare the Roselle seed pods.
Remove and discard the inner seeds from their capsule, either by peeling the red calyces with a knife or by extracting the capsule via pushing it out with a sharp metal tube.
Cut the bottom of each calyx to straighten the edge, then cut the Roselle calyx into equal size pieces.
In a wok, bring water to a boil. Turn off the heat and blanch the Roselle for only a few seconds until they become shiny. It is crucial to keep the fruit flesh textured, so do not overcook! Set aside.
Prepare the rest of the salad ingredients.
Deseed the yellow chilies and remove the inner white membrane. Cut the chilies into small equal-sized squares. Set aside.
Dice the yellow onion into small equal-sized cubes. Set aside.
Peel and slice Thai garlic lengthwise into thin slices. Set aside.
Pick young, equal-sized coriander leaves and soak them in water to freshen them.
Prepare the dressing
Measure the amount of the shrimp curing liquids 'naam sa uh' (น้ำสะเออะ) and mix with fish sauce, white sugar and kaffir lime juice at the ratios indicated.
Plate and serve
You can arrange the salad ingredients on a serving plate separately, with the dressing served separately in a small bowl, or mix and serve immediately.