Best Dragon Roll Recipe - How To Make Dragon Roll Sushi

Ingredients

• 2/3 c. sushi rice
• 2/3 c. water, plus more for rinsing rice
• 1 (2") piece kombu (optional)
• 1 tbsp. unseasoned rice vinegar
• 2 tsp. sugar
• 1/4 tsp. kosher salt
• 1 qt. vegetable oil
• 1/2 c. (or more) all-purpose flour
• 1/3 c. (or more) water
• 1 large egg
• 4 jumbo shrimp (2.5 to 3 oz.), peeled and tails removed
• 2 sheets nori
• 1 avocado, half sliced 1/4" thick, half very thinly sliced, divided
• 1 Persian cucumber, seeds removed and julienned, divided
• 1/2 mango, very thinly sliced
• 2 tbsp. mayonnaise
• 1 tsp. sriracha
• Black sesame seeds, soy sauce, wasabi, and pickled ginger, for serving