Brew the lapsang souchong strong and pour it into a wide, shallow pan. Add the lemon slices, ginger, honey and soy sauce. Bring to a gentle simmer over low heat.
Slide the salmon fillets into the broth skin side down. The liquid should just cover or come close to covering the fish. Keep the heat low — you want a gentle simmer, not a rolling boil.
Poach for 8 to 10 minutes depending on the thickness of the fillets. 8 minutes will give you a slightly translucent centre; 10 minutes will cook the fish through completely. The salmon is ready when it flakes easily when pressed at the thickest point.
Remove the fillets carefully and drain on a paper towel.
While the salmon rests, whisk together all the dressing ingredients until emulsified, or shake in a small jar.
Serve the salmon with steamed asparagus, broccolini or Asian greens. Drizzle the dressing over just before serving.