Tapenade: Pulse all ingredients in a food processor until roughly chopped -- keep it slightly textured, not pureed. Refrigerate.
Toss swordfish with olive oil, lemon juice, oregano, garlic, salt, and pepper. Marinate 20 minutes (no more -- lemon will start cooking the fish).
Thread swordfish alternating with cherry tomatoes onto skewers.
Grill on high heat 3 minutes per side -- swordfish cooks fast and should be just opaque at the center. Overcooked swordfish is dry; pull it while there is still a hint of pink.
Serve immediately with tapenade spooned alongside.