Preheat oven to 375°F. Grease a 9x13-inch baking dish.
Press crescent dough into the dish, sealing seams. Par-bake 8 minutes until lightly set.
Heat oil in a large skillet over medium heat. Soften onion for 3 minutes.
Add ground beef. Cook and crumble until browned, 5–6 minutes. Drain excess fat.
Stir in garlic. Cook 30 seconds until fragrant.
Sprinkle in taco seasoning and add water. Simmer 2–3 minutes to thicken.
Lower heat. Blend in cream cheese until smooth and creamy.
Fold in tomatoes, black beans, and corn. Warm 2 minutes. Season with salt and pepper.
Spread beef mixture over the crust. Sprinkle cheese evenly on top.
Bake 12–15 minutes until the cheese is melted and crust is golden. Rest 5 minutes, then slice.