More than one tradition is at work here. Dill and cucumber, mated in several cuisines, unite in a Greek-inspired salad, while salmon and dill are a typical Scandinavian pairing. Slideshows: Great Grilled Salmon
In a strainer set over a medium bowl, toss the cucumber, tomatoes, and 1/2 teaspoon of the salt and let drain for 15 minutes.
Meanwhile, in a large pot of boiling, salted water, cook the orzo until just done, about 12 minutes. Drain. Rinse with cold water and drain thoroughly. Toss the orzo with the 1/3 cup oil, the lemon juice, the 1/3 cup dill, 1/4 teaspoon of the salt, and 1/8 teaspoon pepper.
Light the grill. Coat the salmon with the 1 tablespoon oil, the remaining 1/4 teaspoon salt, and 1/4 teaspoon pepper. Grill the salmon, skin-side up, for 4 minutes. Turn and sprinkle with the 1 tablespoon dill and the lemon zest. Cook the fish until golden brown and just barely done (the fish should still be translucent in the center), about 3 minutes longer. Serve the fish on the salad.
A good Sancerre or Pouilly-Fumé will make the fresh, bright flavors of this pasta salad sing.