Preheat the olive oil in a non-stick pan over medium heat. Season the salmon with some salt and pepper on both sides and place skin-side down in the hot pan. Sear for 3 - 4 minutes before carefully flipping the filets. Cook for another 3-4 minutes before removing from heat.
In the meantime, combine the mixed salad greens, tomatoes, cucumber, and fresh herbs in a large bowl and toss to combine. Set aside.
To make the dressing, whisk the Dijon mustard, olive oil, and apple cider vinegar in a small glass bowl and season with salt and pepper, to taste. Pour dressing over the salad and toss to combine.
To serve, season the salmon with a squeeze of fresh lemon juice and a few dill sprigs. Serve with herb salad and enjoy!