Bring large pot of salted water to a boil. Add asparagus, and blanch for 1 minute, or until bright green. Drain and transfer asparagus to bowl of ice water to cool, and then drain. Alternatively, you can also steam asparagus in a steamer basket. Place asparagus in refrigerator and chill for at least 30 minutes.
In bowl, stir together roasted red pepper, yogurt, sesame oil, lemon zest, lemon juice, garlic, thyme, salt, cayenne, and black pepper.
Serve red pepper dip alongside chilled asparagus spears. Garnish with toasted sesame seeds if you wish.