1/4 cup radish shoots (leaves with 1/2-inch stem), trimmed, or pea shoots
1 teaspoon black sesame seeds
Ponzu sauce, for dipping
To blanch the carrots and asparagus: Bring a small sauce pot of water to a boil. Submerge the carrots in the water and cook for 1 minute. Remove into a bowl of ice water to cool completely. Strain the carrots and pat dry. Set aside. Add the asparagus to the boiling water and cook for 2 minutes. Remove into a bowl of ice water to cool completely. Strain the asparagus, pat dry and set aside.
To prepare the rolls: Have the rice, vegetables and a small bowl of water ready. Place the nori onto a plastic-lined bamboo mat, coarse side up. Spread about 1 cup of sushi rice evenly over the nori, leaving a 1/2-inch border at the top. Dip your hands in the water to prevent the rice from sticking to them.
Sprinkle half of the radish shoots onto the rice and gently flatten them until they adhere. Sprinkle the rice with 1/2 teaspoon of sesame seeds. Turn the rice-covered nori sheet over.
Leaving a 1-inch border at the bottom and working your way up, arrange each of the vegetables in a straight line. Simultaneously fold the nori sheet and bamboo mat tightly over the vegetables. Press firmly, pulling the mat toward you and shaping into a log. Fold the nori tightly over one more time, and again use the bamboo mat to shape. Remove the bamboo mat.
Moisten the blade of a sharp knife. Cut the sushi roll in half, then cut both halves in half. Halve the remaining rolls one more time to yield 8 pieces. Repeat with the remaining nori, rice and vegetables. Serve with ponzu sauce.