- 1 medium red onion, thinly sliced
- 1 cup unseasoned rice vinegar
- 1/3 cup plus 1/2 teaspoon sugar
- 2 teaspoons kosher salt, plus more
- 11/2 cups jasmine rice
- 3/4 cup unsweetened coconut cream (from a 14-ounce can)
- 1 large jalapeño, thinly sliced
- 3 tablespoons white soy sauce
- 1 1/2 teaspoons finely grated lime zest
- 2 tablespoons fresh lime juice
- 1 1/2 teaspoons toasted sesame oil
- 1/2 teaspoon finely grated peeled ginger
- 1 garlic clove, finely grated
- 12 ounces fluke, cut into 3/4×1/4-inch pieces
- 1/2 cup coarsely chopped unsalted, roasted macadamia nuts or cashews
- 1/2 cup torn cilantro leaves with tender stems
- 1 toasted nori sheet, torn into bite-size pieces
- Place onion slices in a medium bowl. Bring vinegar, 1/3 cup sugar, 2 tsp. salt, and 1/2 cup water to a simmer in a small saucepan over medium-high heat and cook, stirring occasionally, until sugar is dissolved, about 5 minutes. Immediately pour brine over onion and let cool. Cover and chill at least 1 hour.
- Meanwhile, rinse rice until water runs clear (this removes surface starch and keeps rice from getting gummy). Combine rice, coconut cream, and 1 1/2 cups water in a medium saucepan, season lightly with salt, and bring to a boil. Reduce heat to low, cover, and cook until rice is tender, 15–18 minutes. Remove from heat and let sit (keep covered) 10 minutes; fluff coconut jasmine rice with a fork. Keep warm.
- Mix jalapeño, soy sauce, lime zest, lime juice, oil, ginger, garlic, and remaining ½ tsp. sugar in a medium bowl. Add fluke, macadamia nuts, and drained pickled red onion to jalapeño-ginger dressing; season with salt and toss gently to combine. Add cilantro and toss again.
- Divide rice among bowls and top with fluke mixture and pieces of nori.
- Red onion can be pickled 5 days ahead; keep chilled. Dressing can be made 1 day ahead; cover and chill.