Brush the salmon fillets with a little olive oil and season with salt and black pepper.
Grill the salmon over medium-high heat for 4–5 minutes per side, or until cooked through and flaky.
Let the salmon rest for a few minutes before serving.
In a large salad bowl, combine the mixed greens, cherry tomatoes, cucumber, red onion, and feta cheese.
Drizzle the olive oil and lemon juice dressing over the vegetables and toss gently.
Place the grilled salmon on top of the salad.
Serve immediately with extra lemon wedges if desired.