1 tablespoon peanut or vegetable oil
1 cup small-diced onion
1/4 teaspoon salt
1/4 teaspoon freshly ground pepper
2 English cucumbers (1 1/2 of the cucumbers peeled, seeded, and sliced 1/2 inch thick - the rest seeded and cut into small dice for salad)
1 jalapeño, seeded, minced (reserve 1 teaspoon for the salad)
1 can coconut milk (14 ounces)
1 cup packed fresh basil leaves, plus 2 tablespoons chopped
1/4 cup packed fresh cilantro leaves and stems, plus 2 tablespoons chopped leaves
Juice of 1 medium lime (about 1 1/2 tablespoons)
1 tablespoon fish sauce
1/4 cup minced red onion
1. Make the crab salad: In a medium-sized bowl, mix the reserved herbs and jalapeño with the crabmeat, olive oil, reserved lime juice and red onion. Taste and adjust the seasonings, adding a pinch of salt if needed.
2. Heat the peanut oil in a stockpot over medium-high heat. Add the onion, salt, and pepper and sauté for 3 to 4 minutes, or until the onion has softened. Add the cucumber slices and jalapeño and sauté for 2 to 3 minutes more, then add the water, coconut milk, 1 cup basil and 1/4 cup cilantro. Bring to a simmer and cook for 2 minutes. Add half of the lime juice and the fish sauce.
3. Transfer the soup to a blender and blend to a smooth, bright green puree. Let the blender run for about 2 minutes.
4. Strain the soup through a fine mesh strainer, pressing on the solids to extract all of the liquid. Discard the solids.
5. Taste and adjust the seasonings if necessary. The soup should have enough saltiness from the fish sauce, acidity from the lime and a bit of a kick from the jalapeño. Chill the soup in the refrigerator for at least 1 hour. Adjust to your taste.
6. Serve the salad in the middle of wide bowls. Ladle the cold soup around the salad and drizzle some olive oil around the soup.