Season the chicken breast evenly on both sides with the sea salt, black pepper, and dried oregano.
Heat a non-stick skillet over medium-high heat and cook the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
While the chicken cooks, finely shred the red cabbage and grate the carrots.
In a small jar or bowl, whisk together the extra virgin olive oil, apple cider vinegar, and dijon mustard until the dressing is fully emulsified.
Once the chicken is cooked, remove it from the heat and let it rest for 5 minutes before slicing into thin strips.
In a large mixing bowl, combine the baby spinach, shredded cabbage, and carrots.
Drizzle the vinaigrette over the vegetables and toss thoroughly to ensure every leaf is coated.
Transfer the salad to a plate, top with the warm sliced chicken breast, and sprinkle with sunflower seeds.