How to Make It
Bring a large saucepan of water to a boil. Add a large pinch of salt and the lemon juice. In a medium skillet, toast the sesame seeds over moderate heat, shaking the pan a few times, until golden brown, about 4 minutes. Spread the sesame seeds on a plate and let cool completely.
Add the asparagus and carrots to the boiling water and cook for 2 minutes. Drain and spread out on a baking sheet to cool.
In a mini food processor, pulse the sesame seeds until coarsely ground. Add the mayonnaise, rice vinegar, soy sauce, sugar and cayenne and process to blend. Season the dressing with salt.
Transfer the asparagus and carrots to a platter. Drizzle the dressing on top or mix with the vegetables and serve.