Halve the avocado, stone it and remove the flesh from the skin with a tablespoon. Finely dice 3⁄4 and mix with 2 tablespoons lime juice. Cut the remaining avocado into slices and sprinkle with 1 tbsp lime juice
Finely dice the shrimp and salmon, mix with the avocado cubes. Season with pepper. Fold in 1 tablespoon of oil
Place a garnish ring or aluminium foil (approx. 9 cm Ø) folded several times to form a ring on each plate. Spread the tartar evenly in the ring and press down lightly. Carefully loosen and remove the ring with a knife
Sprinkle the tartar with the remaining oil and add 1 blob of crème fraîche and 1 teaspoon of caviar. Sprinkle with pepper. Garnish with avocado slices, dill and lime wedges