Preheat oven to 375. Cut zucchini in half lenghwise, leaving the ends on. Scoop out the centers and save. Mix one clove of finely chopped garlic with 1 T. of olive oil and brush the inside of the zucchini. Sprinkle with salt and place on a baking sheet, cut side down and bake for about 20 minutes (or until tender).
Heat the other tablespoon of oil in a skillet, add the chopped onion, cumin, salt and a few pinches of cayenne. Saute until onion is soft, then add corn, garlic and salt to taste. Saute unti corn is tender, chop and add the reserved zucchini and saute for about 2 minutes more. Remove from heat and add the chiles, cilantro and cheese.
Mound the filling into the zucchinis, place on a lightly oiled baking sheet and bake for 25-30 minutes.