In a medium bowl, combine tuna, cooked rice, onion, celery, garlic, lemon juice, parsley and salt.
Cut the top off of your tomatoes and gently scoop out the insides, leaving the thick wall intact.
Stuff the tomatoes with the tuna and rice mixture.
Place stuffed tomatoes in a greased baking dish (one with high sides works well to help keep the tomatoes standing while they cook. Top each tomato with 1 tablespoon breadcrumbs.
Bake tomatoes for 15-20 minutes, until the flesh begins to wrinkle and a knife inserted into the center of the tuna and rice mixture comes out hot.
Let stand 5 minutes for the juices to settle before serving.