Heat the oven: Preheat to 400°F (200°C).
Lightly oil a large baking dish.
Prep the zucchini: Trim the ends, slice each zucchini lengthwise, and use a spoon to scoop out the centers, leaving a 1/4-inch shell. Chop about half the scooped flesh and set aside; discard any overly seedy bits.
Soften the veg: In a skillet over medium heat, warm olive oil. Sauté onion, bell pepper, chopped zucchini flesh, and a pinch of salt for 4–5 minutes until slightly tender.
Stir in garlic for 30 seconds until fragrant.
Build the filling: Add chicken, black beans, corn, salsa, lime juice, and seasoning. Stir well. Taste and adjust with salt, pepper, or more seasoning.
The mixture should be moist but not soupy.
Season the boats: Lightly salt the inside of each zucchini shell. Arrange them snugly in the baking dish, cut side up.
Fill and top: Spoon the chicken mixture evenly into each boat, mounding slightly. Sprinkle with shredded cheese.
Bake: Cover loosely with foil and bake for 15 minutes.
Remove foil and bake another 8–12 minutes, until zucchini are tender and cheese is bubbly.
Optional broil: For a golden top, broil for 1–2 minutes, watching closely.
Finish: Let rest 3–5 minutes. Garnish with cilantro and add your favorite toppings. Serve with lime wedges.