The key to the short cooking time is to get shrimps that had already been peeled and deveined. If you have to start from scratch and clean the shrimps yourself, the prep time will be longer but there is an advantage. You might want to pound the heads and shells, and press out the juice. Add that juice to your curry sauce for a deeper and richer flavor.
Rinse the shrimps, drain spread on a rack to allow water to drip off.
Place the shallots, garlic, ginger and chilies in a mini food processor, and grind as finely as you can.
Heat the cooking oil in a wok or shallow pan.
Saute (medium-low heat) the ground spices, curry powder, kaffir lime leaves and shrimp sauce for about five minutes or just until the solids are starting to separate from the oil.
Turn up the heat to high, pour in the coconut cream, stir in two tablespoons fish sauce and allow to boil for a minute.
Allow the sauce to boil gently for a minute, taste and add more fish sauce to get a good balance between salty and sweet.
Stir in the shrimps.
Cook, uncovered, just until the shrimps change color.
Turn off the heat and leave the shrimps to cook in the residual heat for another minute.
Taste the sauce, add more fish sauce, if needed.
Ladle rice into bowls, arrange the shrimps on top and drizzle in curry sauce.
Arrange cucumber and tomato slices on the side, garnish with cilantro and serve your shrimp curry rice bowl.