Preheat your grill pan or skillet over medium-high heat. Lightly season the salmon fillet with salt and pepper.
Cook the salmon for about 6-7 minutes on each side, or until it is cooked through and flakes easily with a fork. Remove from heat and let it cool slightly.
While the salmon is cooling, prepare the dressing by whisking together olive oil, lemon juice, salt, and pepper in a mixing bowl.
In a large mixing bowl, combine the mixed greens, cherry tomatoes, cucumber, and red onion.
Once the salmon has cooled, flake it into bite-sized pieces and add it to the salad mixture.
Cut the avocados in half, remove the pit, and scoop out the flesh. Slice the avocado and add it to the salad.
Drizzle the dressing over the salad and gently toss to combine, ensuring all ingredients are evenly coated.
Serve immediately on plates, garnishing with fresh dill if desired.