Stuffed Spaghetti Squash with Tomatoes, Olives, Tuna and String Cheese

2 medium spaghetti squash, halved lengthwise
1 (14-ounce) can diced tomatoes
1/2 cup pimento-stuffed green olives, chopped
1 teaspoon dried oregano
Salt and ground black pepper
2 tablespoons green olive brine (from the olive jar)
2 (6-ounce) cans chunk white tuna in water, drained
String cheese
1/4 cup chopped fresh basil leaves

Arrange the spaghetti squash halves in the bottom of a slow cooker.
In a medium bowl, combine the tomatoes, olives, oregano, and 1/2 teaspoon each of salt and black pepper. Spoon the mixture over the spaghetti squash. Pour the olive brine in the slow cooker. Cover and cook on LOW for 6 to 8 hours or on HIGH for 3 to 4 hours.

When ready to serve, using a fork, "loosen" the squash slightly, creating spaghetti-like strands. Spoon the tomato sauce over the squash, top each piece with some tuna, string cheese, and basil and serve.