In a mixing bowl, combine yuzu juice, ponzu sauce, filtered water, sugar, sesame oil, and a smashed garlic clove. Whisk until smooth.

Carefully slice the sushi-grade yellowtail hamachi into thin pieces, approximately ¼ inch thick. Lay the slices slightly overlapping on a chilled plate.

Drizzle the prepared yuzu ponzu sauce over the hamachi slices, ensuring even coating. Let it sit for a minute.

Sprinkle finely sliced shallots, fresh cilantro leaves, and serrano pepper slices over the dressed hamachi. Add a pinch of lemon zest and flaky salt.

Serve immediately for the best taste and texture.