Bring pot of salted water to boil.
Meanwhile, whisk lemon juice, sugar, shallot, 1/2 teaspoon salt, 1/4 teaspoon pepper, mustard and oil in small bowl.
Transfer 1/4 cup dressing to plastic food bag or glass dish; add turkey; turn to coat. Marinate 15 minutes. Reserve remaining dressing.
Add tortellini to boiling water; cook according to package directions. Drain; rinse; drain.
Prepare outdoor grill with medium-hot coals, or heat gas grill to medium-hot, or heat oven broiler.
Combine cherry tomatoes and spinach in large serving bowl.
Remove turkey from marinade; discard marinade. Grill or broil cutlets 6 inches from heat, 5 minutes per side depending on thickness, or until internal temperature registers 170°F. Cut turkey into bite-size pieces.
Add drained pasta to mixture in bowl. Add turkey, reserved dressing and walnuts; toss to mix. Serve slightly warm or chilled.