In a bowl, combine the turkey thighs with the garlic, herbs, lemon zest and juice, olive oil, cumin, salt, and pepper. Coat the turkey thoroughly in the marinade, spreading the marinade between the meat and the skin as well. Cover, refrigerate, and allow to marinate overnight (about 12 hours).
Heat your grill to high, and sear the turkey thighs skin-side down for about 15 minutes. Flip the turkey thighs, reducing the heat in your grill until it reaches about 350 degrees. Cover and continue to cook (approximately 45 minutes at 350 degrees F) until the turkey’s internal temperature reaches 180 degrees F. During this process, check the turkey periodically to make sure it isn’t drying out.
(Alternatively, you can roast the turkey in your oven. Simply heat your oven to 425 degrees F and roast for 15 minutes. Reduce the heat to 350 degrees, and continue roasting for another 45 minutes.)
Once cooked, allow the turkey to rest on a cutting board. While the turkey is resting, prepare the farro salad. Combine the lemon zest and juice, garlic, olive oil, and salt and pepper to taste. Toss in the cooked farro, parsley, mint, and arugula.
To serve, add a bed of salad to the plate. Slice the turkey and serve on top, along with a sprinkling of feta cheese.