In a large bowl, combine the tuna, yogurt, onion, celery, adobo sauce, dill, tahini, honey, lemon juice, and chili powder. Mix well. Season with salt and black pepper to taste.
Layer 2 bread slices, each with the cheddar cheese, tomato, and tuna mixture. Top with the remaining 2 bread slices.
On a heated griddle, add a little butter. Add the sandwiches and cook for 1-2 minutes per side, until golden brown and crispy.
Enjoy immediately!
