Preheat the oven to 350 degrees, and spray a 9×13-inch casserole dish with nonstick spray.
In a large skillet, brown the ground beef over medium heat, breaking the meat apart it cooks. Drain off the grease, and pour the cooked meat into a large bowl.
While the meat is cooking, fill a large pot halfway with water, and bring it to a boil. Add the jumbo shells, and cook until al dente. Refer to the time chart on the box of noodles.
Add the taco seasoning to the meat mixture, and stir well.
Then add half of the salsa and half of the cheese, and stir to combine. Set aside.
Once the shells are cooked, drain the water, and rinse the shells with cold water to cool them a bit for easier handling.
Fill the shells with a heaping spoonful of the taco meat mixture, and place in a single layer in the prepared casserole dish.
Pour the remaining salsa over the shells and top with the remaining cheese. Add the diced tomatoes and chopped cilantro over top of the cheese.
Bake for 30 minutes. Remove from the oven, and serve.