Season the turkey with the sage, ½ teaspoon of the salt, and ⅛ teaspoon of the pepper. Warm 1 tablespoon of the oil in a heavy medium skillet over medium-high heat. Add the turkey and cook until browned, 3 to 4 minutes per side. Reduce the heat to medium low and cook until no longer pink in the center (160°F internal temperature), 4 to 5 minutes. Remove the turkey to a cutting board and let it stand for 5 minutes.
Meanwhile, whisk together the preserves, vinegar, and remaining 3 tablespoons of oil, ¼ teaspoon of salt, and ⅛ teaspoon of pepper in a large bowl. Pour out ¼ cup of the dressing and set it aside. Add the spinach and onion to the bowl with the dressing that’s left and toss to coat. Divide the greens among four salad plates and evenly scatter on the tangerine pieces, almonds, and cheese.
Thinly slice the turkey and drape it over the top of the salad. Drizzle on the reserved dressing.
Tip: You can cook the turkey up to a day ahead. Just keep it refrigerated; then reheat it in the microwave and slice it just before serving.