In a small bowl stir together oil, soy sauce, vinegar, sugar, salt, and red pepper flakes until sugar and salt are dissolved. In a large saucepan of salted boiling water cook capellini until tender and drain in a colander. Rinse noodles under cold water until cool and drain well. In a large bowl toss noodles with sauce, cucumber, and scallion or coriander until combined well and divide between 2 plates. Sprinkle noodles with sesame seeds. Serves 2. Gourmet July 1994