Preheat oven to 375℉ and line a large baking sheet with parchment paper for easy cleanup, or spray a large baking dish with cooking spray.

Prepare the zucchini boats by cutting off the stems and slicing the zucchini in half lengthwise. Use a spoon to scoop out the flesh and seeds. Set the prepared zucchini on the lined baking sheet.

Heat the olive oil in a medium skillet over medium-high heat. Add the onions and cook until softened and translucent, about 5 minutes.

Add in the garlic, ground beef, bell pepper, and taco seasoning. Break up the ground beef and stir to combine. Cook until all the meat has browned and is cooked through, about 8-10 minutes

Stir in the black beans, corn, ½ cup of shredded cheese, and salsa. Cook for an additional 5 minutes, until the black beans and corn are warmed through and the cheese is melted.

Assemble Mexican zucchini boats by scooping equal amounts of filling, about 3-4 tablespoons, into each zucchini. Top with the remaining 1 cup of shredded cheese.

Cover with aluminum foil and bake for 25-30 minutes, until zucchini is soft and tender.

Remove foil, garnish with chopped cilantro, and serve immediately.