One 2 1/2-pound center-cut skin-on salmon fillet, cut into 6 equal pieces
2 tablespoons extra-virgin olive oil
1 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
2 English (hothouse) seedless cucumbers, peeled and cut into 8 pieces
3/4 cup finely sliced fennel, feathery fronds reserved for the garnish
6 Medjool dates, pitted and cut in slivers
1/3 cup coarsely chopped walnuts
2 tablespoons minced fresh chives
2 tablespoons fresh lemon juice (1/2 a large lemon)
6 tablespoons fruity olive oil (preferably from Spain)
Medium-coarse sea salt (preferably Maldon from England)
Fresh ground black pepper