Spicy Watermelon Onigiri

Name: Spicy Watermelon Onigiri
Ingredients: 2 cups white short-grain sushi rice, rinsed until water runs almost clear; 1 garlic clove; 1 whole star anise pod; 2 whole allspice; ¼ cup coconut sugar or vegan granulated sugar; ¼ cup unseasoned rice vinegar; 1 Tbsp. grapeseed oil; 3 tsp. sea salt, divided, plus more; 2 cups ⅛ cubes watermelon (from about ¼ small watermelon); ¼ cup vegan mayonnaise; 2 tsp. soy sauce; 1 tsp. Sriracha; 1 tsp. white miso; ¼ tsp. toasted sesame oil; 3 toasted nori sheets, cut into 2-thick strips; Furikake (for serving)