Place salmon fillets in a deep dish and combine all other curing ingredients in a bowl.
Pour the curing mixture over the salmon fillets in the dish.
Weight down the salmon with a smaller dish and a heavy object to flatten.
Cover and refrigerate for 1-2 days, turning the fillets twice daily.
Rinse the salmon, pat dry, and carve into thin slices.
Blend egg components, mustard, wasabi, vinegars, and sugar into a purée.
Gradually whisk in olive and grapeseed oils until the dressing thickens then season.
Blend dill and oils into a fine purée to create dill oil.
Carve 20 balls from the peeled cucumbers using a melon baller.
Toss cucumber balls with 2 tablespoons of olive oil and 50ml sparkling water.
Microwave the cucumber mixture for one minute and drain.
Mix cooked potato cubes with the cucumber and lemon vinaigrette.
Fry focaccia cubes in 1 tablespoon of olive oil until golden.
Caramelise caster sugar in a pan and coat the fried croutons.
Stir in lemon zest, juice, and remaining oil to finish the croutons.
Assemble plates with dressing, ginger, fennel, roe, salad, salmon, and garnish with dill oil and cress.