Preheat oven to 375°. Line a baking sheet with parchment.

Stir oil, maple syrup and sesame oil together in a small bowl.

Peel sweet potato and cut, lengthwise, into strips that are just under ½ inch thick, as if you were making sweet potato fries. Rub with oil and maple syrup mixture, or place into a bowl and toss to coat. Arrange strips on baking sheet. Bake about 25 minutes, until tender, gently turning halfway through.

While sweet potatoes bake, place rice into a fine mesh strainer and rinse under cold, running water for 1-2 minutes.

Place rice into a small saucepan with water, vinegar and salt. Place over high heat. Stir a few times to incorporate. Bring to a simmer, lower heat, cover and allow to continue simmering for about 20 minutes, or until all liquid is absorbed. Allow to sit for 10 minutes before uncovering.

Place a bamboo mat onto work surface and fill a small dish with water for wetting your hands. Place one of your sheets on the bamboo mat. Using wet hands, cover nori with a thin layer of rice. Arrange a third of your sweet potato strips in a single line along the width of nori, about one inch away from you. Arrange a few scallion pieces right alongside the sweet potato strips.

Take the bamboo mat and end of nori closest to you and tightly roll it over your fillings. Tuck the end of the nori in and continue rolling, using the mat to press your roll tight. Once completely rolled, slice into eight pieces.

Repeat using your remaining nori sheets and fillings.

Sprinkle with sesame seeds and serve with soy sauce, wasabi and pickled ginger.