2/3 cup crunchy peanut butter
1 to 2 tablespoons red curry paste
2 teaspoons rice wine vinegar
Juice of 1 lime, plus wedges for serving
1/3 cup fresh cilantro leaves, plus more for sprinkling
2 scallions, thinly sliced
1 cucumber, peeled, seeded and cut into thin strips
1 large carrot, coarsely grated
Red pepper flakes or chili paste, for serving (optional)
Bring a large pot of salted water to a boil. Add the spaghetti and cook as the label directs. Reserve about 1/2 cup cooking water, then drain in a colander and rinse under cold water. Shake off the excess water.
Meanwhile, puree the peanut butter, curry paste, vinegar, lime juice, cilantro, 1/2 cup water and 1 teaspoon salt in a food processor or blender until smooth. Toss the spaghetti with the peanut sauce, scallions, cucumber and carrot in a large bowl until coated. Season with salt and stir in some of the reserved cooking water to loosen the sauce, if necessary. Put in the refrigerator to chill for a couple of hours. Transfer to bowls and top with more cilantro and pepper flakes, if desired. Serve with lime wedges.