Cut zucchini in half lengthwise and scoop out insides, reserving them for later. Place zucchini halves cut side-up into bottom of 9”-x-13” baking dish and drizzle with 1 tablespoon oil; season with salt and pepper. Bake until zucchini turns bright green and is just beginning to soften, 10 minutes.
Heat oil in a large skillet over medium heat. Add onion and reserved zucchini and cook until soft, about 5 minutes. Stir in garlic and cook until fragrant, about 1 minute more. Add ground beef, breaking up the meat with a wooden spoon. Cook until beef is no longer pink, about 6 minutes. Drain fat.
Stir in chili powder, cumin, and paprika, then season with salt and pepper. Stir in black beans, cherry tomatoes, and corn.
Spoon beef mixture into zucchini then top with cheeses. Bake until zucchini is just tender and cheeses are melted, about 15 minutes. Garnish with cilantro before serving. Enjoy!