In a covered large saucepan, cook asparagus in boiling water for 1 minute. Using tongs, transfer asparagus to a large bowl of ice water. Let stand for 2 minutes. Drain well and pat dry with paper towels. Place asparagus in a large resealable plastic bag.
In a small bowl, whisk together soy sauce and sesame oil; pour over asparagus. Seal bag. Chill for 1 to 4 hours. Drain, discarding soy sauce mixture. To serve, sprinkle asparagus with sesame seeds.