Make Marinade /Dressing: Whisk together all of the marinade/dressing ingredients in a bowl. Take 2 tablespoons of it and place onto large shallow bowl reserving the rest for the salad. Season salmon with a pinch of salt and pepper and place in bowl with the dressing. Toss to coat with the marinade.
Sear salmon: Heat remaining 1 tablespoon of oil in a skillet or grill pan over medium-high heat and cook sear salmon for 3-4 minutes. Test the salmon; when the bottoms release fairly easily, it’s ready to flip. Turn each filet over, and cook for an additional 1-2 minutes, until it’s cooked through and has a golden crust. Remove from the heat and set aside.
Assemble the Salad: Combine lettuce, tomatoes, bell pepper, cucumber, olives, herbs, avocado, feta and onion in a large bowl or on a large platter. Drizzle with about half of the dressing and toss to combine. Top with salmon and additional dressing, to taste, either on the serving dish or on individual plates.
