Make Fish Cakes:

1. Beat the egg whites in a bowl with a whisk until foamy-like a soft peak meringue. In another large bowl combine the greens beans, garlic, salt, and sugar.
2. Roll the leaves of the kaffir lime tightly like a cigarette and slice across as thinly as possible. 
3. In a food processor, process the fish until it is coarsely chopped. Then add the rice flour, curry paste, and kaffir lime leaves and continue processing for 30 seconds to 1 minute until it is a smooth thick paste. Add it to the bowl of green beans. Mix everything together and then gently fold in the egg whites. (Mix 1/2 of the egg whites into the fish mixture first to lighten the base. Then add the rest of the egg whites, gently folding them into the mixture, keeping as much of the air as possible.)

Portion, Shape, and Fry:

1. Portion the patties using either an ice cream scoop or a large spoon-about ¼ cup. Using your hands, shape the patties, dipping your hands lightly in water to keep the fish from sticking to your hands. Place the fish patties on a large plate or tray. (The mixture can be a little sticky, so you can first line your tray with plastic wrap to keep your paties from sticking to the tray.)
2. Heat 4 tablespoons of the oil in a large skillet over medium heat. 
3. Gently place 6-8 patties into the pan and cook for 3 mins. Flip them and cook for another 2 mins. Transfer to a paper towel lined plate to drain off oil. Cook off the remaining patties the same way adding more oil as needed.
4. Serve hot with dipping sauce.

For the Dipping Sauce:

1. In a small saucepan combine tamarind pulp, sugar, rice wine vinegar, cornstarch, water, minced garlic, salt, and pepper.
2. Stir the mixture and set the pot on medium high heat and continue to stir until the mixture thickens 1-2 mins. 
3. Let the sauce cool to room temperature.
4. While you are waiting for the sauce to cool down, slice the cucumber. Then stack the slices and cut it again into thin strips. Finally stack the cucumber strips and cut across them to create a fine dice. Put the diced cucumbers into a bowl.
5. Add the serrano chilis, chopped shallots, and cilantro to the bowl of cucumbers.
6. Pour the cooled sauce over the chopped veggies and stir to combine. Refrigerate until ready to serve fish cakes. Taste the sauce before serving and adjust seasoning as needed.