Preheat the oven to 400°F. Place the salmon fillets on a baking sheet lined with parchment paper. Drizzle with 1 tablespoon of olive oil and season with salt and pepper. Bake for 12-15 minutes, or until the salmon is cooked through and flakes easily with a fork. Let it cool slightly, then flake into large pieces.
While the salmon is baking, prepare the lemon dressing. In a small bowl, whisk together 1/4 cup olive oil, lemon juice, Dijon mustard, honey, salt, and pepper until well combined.
In a large salad bowl, combine the mixed salad greens, cherry tomatoes, cucumber, red onion, avocado, and feta cheese.
Add the flaked salmon to the salad bowl and drizzle with the lemon dressing. Toss gently to combine all ingredients without breaking up the salmon too much.
Serve immediately, or chill in the refrigerator for 15-20 minutes before serving for a refreshing option.