1. Cut both types of salmon into very small cubes.
2. Add finely chopped red onion (4 tbsp), half of the grated lemon zest, and the peeled, seeded, and finely diced cucumber.
3. Add the unpeeled and finely diced apple, chopped dill (2 tbsp), oil, fleur de sel, and pepper.
4. Mix, cover, and let it rest in the fridge for at least 30 minutes (a few hours if possible).
5. Prepare the avocado cream: put the avocado flesh in a blender, add the lemon juice (used for the tartare zest), chopped cilantro, and the remaining indicated ingredients. Blend until you obtain a thick and smooth cream. Transfer it to a piping bag.
6. Prepare the horseradish oil: finely grate the zest of 1 lemon and squeeze the juice of 2 lemons. Add honey and mix well. Add horseradish and oil. Mix.
7. Arrange the tartare in quenelles (or with small circles) on plates, add small dollops of avocado cream, and decorate according to your preferences with pomegranate seeds, sesame seeds, herbs, apple sticks, red onion...
8. Serve chilled, with toasted bread slices.