Mix the lime juice with all the other ingredients up to and including the salt, mix in the celeriac, cover and leave to infuse for approx. 30 mins. at room temperature.
Blitz the sesame seeds in a food processor, place in a shallow dish. Mix the horseradish and salt. Spread the horseradish over the fish, then coat with the sesame seeds, press down firmly.
Heat the oil in a frying pan, fry the salmon (skin side down first) for 3 mins., turn and cook for approx. 3 mins. Combine the honey and water, drizzle over the salmon. Serve the salmon with the salad.