CHILL EVERYTHING — Put plates in the freezer, fish in the coldest part of the fridge.
MAKE THE DRESSING — Whisk together lemon juice, lime juice, yuzu, and oil. Add orange zest and a pinch of salt. Taste — it should be bracingly tart.
SLICE THE HAMACHI — Cut against the grain into ¼-inch pieces. Arrange in a single layer on cold plates.
DRESS THE FISH — Spoon 1–1½ tbsp dressing over each plate. Fish should glisten, not swim. 60 seconds max before serving.
GARNISH AND SERVE — Scatter fresno and serrano rounds over the fish. Tuck in orange supremes. Finish with microgreens, sesame seeds, and a final pinch of flaky salt. Serve immediately.