01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Place salmon fillets on the baking sheet. Drizzle with olive oil, season with salt and pepper, and roast for 10 minutes or until just cooked through. Remove from oven, let cool slightly, then flake into large pieces with a fork. Squeeze lemon over salmon.
03 - In a bowl, whisk together Greek yogurt, mayonnaise, lemon juice, parsley, chives, tarragon, garlic, anchovies, salt, and pepper until smooth. Taste and adjust seasoning if needed.
04 - In a large bowl, gently toss cucumber, tomatoes, radishes, avocado, and red onion. Add flaked salmon and half the dressing. Gently toss to combine.
05 - Separate lettuce leaves and arrange on a platter. Fill each with a generous spoonful of the salmon salad. Drizzle extra dressing over the top.
06 - Serve immediately, garnished with extra herbs if desired.