Gently shred the crab meat, pulling it lengthwise into long strips. Combine with carrots, cucumber, and mango into a bowl.
In a small mixing bowl combine the mayonnaise, sriracha, orange juice, rice wine vinegar, tamari, sugar, and serrano pepper. Season to taste, adding more sriracha and serrano if you prefer it spicier.
Pour dressing over the salad and gently toss to coat. Top with the sesame seeds.
Notes
Cut all your vegetables into thin long pieces of equal size.
If you can't find an English or Persian cucumber, be sure to remove the seeds before cutting.
To toast sesame seeds, place in a dry saute pan over medium heat for 1 minute.
Make Ahead: Store the salad and dressing separately. Toss to combine and add the sesame seeds right before serving. The salad will keep for 2 days but best when made the day of serving.