Mix together olive oil, garlic, chopped cilantro, lime juice, salt, oregano and jalapeno in large shallow glass dish. Add the turkey cutlets; turn cutlets over to coat with marinade. Cover dish and refrigerate for at least 1 hour, turning the cutlets occasionally.
Grease stove-top grill pan. Heat over medium-high heat. Or prepare outdoor grill with hot coals, or heat gas grill to hot, or heat oven broiler.
Place turkey cutlets in grill pan, on outdoor grill or under boiler; grill or broil about 3 minutes on each side or until an instant-read meat thermometer inserted in centers of turkey cutlets registers 170°F. Remove turkey cutlets; keep warm. Cook sweet green pepper and onion in grill pan, on outdoor grill or under broiler until tender, about 5 minutes on each side.
Gently warm the flour tortillas according to the package directions.
Slice the turkey cutlets into 1/2-inch-wide strips. Serve turkey and vegetables with flour tortillas, avocado and sour cream.
Let diners make their own tacos, rolling up the filling into the tortillas.
Set out little bowls of additional chopped cilantro and lime wedges for garnish if you wish.