Heat a large straight sided skillet over medium high heat. Add olive oil and swirl around to cover the bottom of the skillet.
Add onion and 1/2 teaspoon salt, cook stirring frequently until the onions are translucent, about 3 to 4 minutes. Stir in curry paste and cook 30 seconds and blend well.
Stir in coconut milk, 1 cup of water and another 1/2 teaspoon salt.
Squeeze tomatoes juice into the curry mixture, then drop the tomatoes. Boil for 1 minute. Stir in the couscous and peas and mix well. Scatter shrimps on top in a single layer, return to a boil.
Cover and reduce the heat to medium low and simmer until the shrimps are just cooked through, 5 to 7 minutes.
Serve hot in the skillet and drizzle with olive oil lightly.