For the roasted salmon: Preheat the oven to 450 degrees F. Line a cooking sheet with foil and lightly oil.
Pat the salmon dry. Check for bones by running your hand over the salmon from the thinnest to thickest end. Remove any bones. Sprinkle the salmon with the 2 teaspoons oil, lemon zest salt and pepper. Cook the salmon until just cooked through, 7 to 8 minutes. Let the salmon cool slightly, then flake with a fork.
For the yogurt sauce: Whisk the yogurt, 1 tablespoon water, lemon zest, juice, mint, salt and pepper in a bowl until combined.
For the Greek salad: Toss the olives, tomatoes, lettuce, scallion and cucumber in a medium bowl. Whisk the vinegar, oregano, salt, pepper and garlic powder in a small bowl. Gradually add the oil, whisking until emulsified. Pour the dressing over the salad and toss. Sprinkle the feta on top.
Serve the flaked roasted salmon on top of the Greek salad and drizzle with the yogurt sauce.