Prepare a large bowl of ice water and set it aside.
Steam the asparagus until it is tender-crisp, which should take about 1 minute. Immediately transfer the cooked asparagus to the bowl of ice water to shock it and stop the cooking process.
Once cooled, drain thoroughly.
In a separate large bowl, whisk together the wasabi paste, Dijon mustard, rice vinegar, honey or syrup, sesame oil, sea salt, and red pepper flakes until well combined.
Add the drained asparagus and sesame seeds to the dressing, and toss gently to coat everything evenly.
Refrigerate until chilled, for about 1 to 2 hours, to allow the flavors to meld.
Serve chilled.
Adjust the heat to your liking. You can easily add more wasabi paste or red pepper flakes for an extra kick, or reduce them for a milder flavor.