Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish or line it with parchment paper for easy cleanup.
In a large bowl, combine the chopped cooked corned beef, drained sauerkraut, shredded Swiss cheese, and creamy Thousand Island dressing. Add salt and pepper to taste, and sprinkle in the caraway seeds if using. Stir everything until evenly mixed.
Unroll the refrigerated crescent roll dough and carefully separate it into triangular sections. Press the perforations together to form a solid sheet or layer the triangles overlapping slightly to create a base.
Place the dough sheet or layered triangles into the prepared baking dish, pressing gently to cover the bottom. Spread the corned beef mixture evenly over the dough. Add another layer of dough over the filling or fold the edges over the filling to create a rustic crust.
Bake in the preheated oven for 20-25 minutes until the crescent dough is golden brown and cooked through, cheese melted and bubbly, and edges crisped.
Let the Reuben bake cool for a few minutes before slicing into squares or triangles. Serve warm with extra Thousand Island dressing or a side of pickles.