Preheat oven to 350 degrees. Combine the ground beef and sweet peppers in a large skillet over medium heat. Chop the beef into small pieces. Stir in the salt, pepper and dry taco seasonings until fully combined. Cook stirring frequently until the beef is no longer pink.
In a medium mixing bowl whisk together the sour cream, mayonnaise, and dry ranch seasoning until fully combined and smooth. Set aside until the beef is fully cooked. Once the beef is cooked drain excess fat. Set aside. Separate the tops and bottoms of the hamburger buns.
Place the buns side by side, in a single layer, in a 3-quart casserole dish. Use hands and flatten the buns until they are the same thickness and cover the bottom of the casserole dish. Place the zucchini slices in a single layer over the buns. Spoon the cooked beef mixture evenly over the zucchini. Spread the tomatoes evenly over the beef.
Spread the sour cream mixture evenly over the tomatoes. Sprinkle both cheeses evenly over the sour cream mixture. Place in preheated oven. Bake for 25 to 30 minutes until the cheese is melted and bubbly. Once baked, remove from the oven and let rest for 5 minutes before serving. When ready to serve, slice into desired pieces and serve warm.