Sprinkle the salmon filets with salt and pepper. Heat oil and butter in a medium skillet over medium-high heat. Add the salmon and cook 3 minutes per side, or until the internal temperature of the fish reaches 145°F. Transfer fish to a plate and cover with foil. Meanwhile, get the salad started.
In a small bowl, whisk together all the ingredients for the vinaigrette. Set aside or refrigerate if not used right away.
In a large bowl. combine tomatoes, cucumbers, radishes, and red onions. Pour the vinaigrette over the vegetables and gently toss to coat them.
Place a large handful of arugula in a serving bowl. Add the marinated veggies, Top with salmon pieces and olives. Enjoy!
Notes
I added thinly sliced roasted potatoes, however this is optional.