Step 1

Line a rimmed baking sheet with a kitchen towel or several layers of paper towels; set aside. Bring 2 cups white short-grain sushi rice, rinsed until water runs almost clear, 1 garlic clove, 1 whole star anise pod, 2 whole allspice, and 2½ cups cold water to a boil in a medium saucepan over medium-high. Reduce heat to low, cover pan, and cook until water is evaporated and rice is tender, 18–20 minutes. Remove from heat and let sit, covered, 10 minutes; discard garlic, star anise, and allspice.

Step 2

Meanwhile, cook ¼ cup coconut sugar or vegan granulated sugar, ¼ cup unseasoned rice vinegar, 1 Tbsp. grapeseed oil, and 1 tsp. sea salt in a small saucepan over medium heat, stirring to dissolve sugar. Let cool slightly.

Step 3

Meanwhile, place 2 cups ⅛" cubes watermelon (from about ¼ small watermelon) in a colander set over a bowl and sprinkle with 2 tsp. sea salt; toss to coat. Let sit 10–15 minutes, then drain off any liquid collected in bowl.

Step 4

Transfer drained watermelon to prepared baking sheet and use towel to press out excess moisture. (Don’t worry about being gentle—you want to press out as much liquid as possible!) Transfer watermelon to a medium bowl.

Step 5

Whisk ¼ cup vegan mayonnaise, 2 tsp. soy sauce, 1 tsp. Sriracha, 1 tsp. white miso, and ¼ tsp. toasted sesame oil in a small bowl until smooth. Add half of sauce to watermelon and mix to coat evenly; season with salt (you want the filling to be on the saltier side). Add more sauce if you’d like, but make sure the filling isn’t overly saucy otherwise it will seep out of the rice balls.

Step 6

Set up a workstation with a small bowl of water, a small dish of sea salt, seasoned cooked rice, and watermelon filling.

Step 7

To make 1 onigiri, scoop ½ cup rice onto work surface. Dip your hands in water to moisten, then rub them with a little sea salt. (This will prevent the rice from sticking to your hands and will also flavors the onigiri.) Cupping rice in your nondominant hand, use your finger to make a shallow well in the center of the rice mound; fill with 1 tsp. watermelon filling. Using your hands and moistening with more water as needed to prevent rice from sticking, gently but firmly shape rice into a ball, fully enclosing watermelon mixture.

Step 8

Place rice ball back on surface and flatten lightly. Using the side of a wet chef’s knife, gently push into a triangle shape. Wrap a strip of toasted nori from 3 toasted nori sheets, cut into 2"-thick strips, and sprinkle with furikake.

Step 9

Repeat with remaining rice, watermelon filling (you won’t use all of it), nori strips, and furikake to make 11 more onigiri.