Dice onion and celery. In a bowl combine tuna, mayo, onion, celery. Add spices.
Heat Panini press to desired temperature. Place a slice of bread on press followed by a scoop of tuna salad. Place one slice of Swiss Cheese and another slice of Sourdough Bread on top of tuna. Lower Panini press lid and head for 5 min or follow your panini press instructions. Repeat with remaining sandwiches. Serve hot!