Pat the salmon dry and season both sides with 1/2 teaspoon salt and 1/4 teaspoon black pepper.
Heat 1 tablespoon olive oil in a skillet over medium-high heat until shimmering.
Sear the salmon 3–4 minutes per side, or until cooked through and opaque in the center; remove from heat and set aside.
In a large bowl, combine chopped Romaine, chopped tomatoes, chopped cucumber, sliced red onion, sliced olives, and crumbled feta.
Make the dressing: in a small jar or bowl, whisk together 1/4 cup olive oil, 2 tablespoons lemon juice, 1 tablespoon honey, 1 teaspoon minced garlic (or 1/2 teaspoon garlic powder), 1/2 teaspoon dried oregano, 1/2 teaspoon salt, 1/4 teaspoon black pepper, and 1/2 teaspoon Dijon mustard until emulsified.
Pour the dressing over the salad and toss gently to combine.
Divide the dressed salad between plates and top with the seared salmon to serve.