Pat the chicken breast dry with a paper towel and season both sides evenly with sea salt, black pepper, dried oregano, and fresh lemon zest.
Heat 0.5 tbsp of the olive oil in a medium non-stick skillet over medium-high heat until shimmering.
Place the chicken in the skillet and cook for 6-7 minutes per side, or until the exterior is golden and crispy and the internal temperature reaches 165°F.
While the chicken is cooking, whisk together the remaining 0.25 tbsp olive oil, lemon juice, and Dijon mustard in a small bowl to create the vinaigrette.
In a large salad bowl, combine the mixed greens, sliced cucumber, halved cherry tomatoes, and finely diced red onion.
Drizzle the vinaigrette over the salad and toss gently to ensure all the vegetables are lightly coated.
Remove the chicken from the skillet and let it rest for 3 minutes before slicing into thin strips.
Top the dressed salad with the sliced chicken and garnish with the sliced almonds for added texture.