Prepare your pasta according to directions. When cooked through, drain and set aside to cool. To a large bowl add tuna, hard boiled eggs and celery. Prepare your "dressing" by combining Greek yogurt, mayo, mustard, lemon pepper, onion powder, apple cider vinegar, salt and pepper. Add your cooled pasta to large bowl along with your dressing. Gently stir to combine. Taste for salt and pepper and adjust.