In a small bowl, whisk together olive oil, lemon juice, Dijon mustard, minced garlic, salt, and pepper until emulsified. Set aside.
In a large bowl, combine flaked salmon, diced cucumber, red onion, dill, and capers.
Pour the dressing over the salad and toss gently to combine. Be careful not to break up the salmon too much.
Taste and adjust seasoning with more salt, pepper, or lemon juice if needed.
For best flavor, let the salad rest in the fridge for 15–30 minutes before serving. Garnish with extra dill and optional feta.
