Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
Unroll crescent dough into the dish, press seams to seal, and bake 8–10 minutes until just set. Let cool slightly.
Warm the olive oil in a large skillet over medium heat. Sauté onion and bell pepper until softened, 3–4 minutes.
Add ground beef and cook, breaking it up, until browned. Drain excess fat.
Stir in garlic and taco seasoning; cook 30 seconds. Add water and salsa, then mix in beans and corn. Simmer 2–3 minutes to thicken.
Beat cream cheese and sour cream in a bowl until smooth and spreadable.
Spread the cream mixture over the parbaked crust. Spoon the beef mixture on top and sprinkle with shredded cheese.
Bake 12–15 minutes, until cheese is melted and edges are golden. Rest 5 minutes.
Scatter olives and green onions over the top. Slice into squares and serve.