Preheat your oven to 400°F and line a baking sheet with parchment paper.
Peel and dice the sweet potato into half-inch cubes, then spread them evenly on the prepared baking sheet.
Lightly mist the potatoes with a small amount of oil and roast for 20-25 minutes until tender and golden brown.
While the potatoes roast, place a non-stick skillet over medium-high heat and add the ground turkey.
Season the turkey with half of the salt, pepper, and dried oregano, breaking it apart with a spatula until fully cooked and browned.
In a large mixing bowl, combine the mixed salad greens, halved cherry tomatoes, and thinly sliced red onion.
Whisk together the olive oil, lemon juice, and the remaining salt, pepper, and oregano in a small jar to create the dressing.
Add the warm roasted sweet potatoes and the cooked turkey to the salad bowl.
Drizzle the lemon-herb dressing over the mixture and toss gently to combine before serving immediately.