Soak the dried guajillo chilli in hot water for about 20 minutes.
Prepare the tiger prawns. Devein the prawns with a toothpick. Cut off the horn, swimmers, legs and whiskers.
Marinate the prawns with 1 tsp of salt, sprinkling half of it on one side. Rub them to spread the salt evenly. Repeat for the other side. Set it aside.
Make the chilli paste for the sauce. Cut both chillies into smaller pieces over the blender. Blend until they turn into a fine paste. Set it aside.
Mix tapioca flour and 15ml of water in a small mixing bowl until well combined. Set it aside.
Heat 400ml of cooking oil in a wok over medium heat for about 8-10 minutes, or until the dipped tips of cooking wooden chopsticks release tiny bubbles.
Coat the marinated prawns generously with crispy flour, on both sides. Make sure to cover the head as well.
Deep fry the prawns, 2 at a time, for 2 minutes, flipping them when the colour changes. Remove the prawns with a strainer and let them rest on a cooling rack. Repeat with all the prawns until completed. Switch off the heat.
Add 2 tbsp of cooking oil to a non-stick pan over medium heat.
Fry minced garlic for about 2 minutes, or until crispy. Remove them from the pan and set them aside.
Fry the blended chilli paste for about 2 minutes, or until slightly dried.
Add tamarind juice, 1/4 tsp of salt, 1 tbsp of sugar and tomato sauce. Mix until well combined, and continue to cook until it comes to a rolling boil. If it is too thick, add 50ml of water.
Mix in the yellow onions, red capsicum, yellow capsicums and green capsicum, until well-coated with the sauce. Braise for 1.5 minutes for a cooked and crunchy texture. Allow to cook for 3 minutes for a soft texture.
Taste and adjust. I added 1/2 tbsp of sugar to mellow out the spiciness and sourness. Stir to mix.
Add and mix in the tomato wedges, cooking them slightly.
Add the flour slurry and stir until well combined. Switch off the heat.
Add the fried prawns, gently stirring them to coat them with the sauce. Add spring onions and fried garlic. Mix them until well combined.
Dish it out onto a serving plate. Sprinkle some chopped spring onions and serve immediately.