Heat oven to 375°F. Using teaspoon, scoop out zucchini seeds and pulp, leaving a 1/4 to 1/3-inch wall. Chop 1/2 cup of the zucchini pulp.
In medium bowl, combine zucchini pulp, onion, feta cheese and corn; mix well. Spoon about 1/4 cup mixture into each zucchini half, mounding slightly. Place stuffed zucchini in ungreased 13x9-inch pan.
Bake at 375°F. for 25 to 30 minutes or until stuffing is thoroughly heated and zucchini is crisp-tender. Sprinkle with Cheddar cheese. Bake an additional 1 to 2 minutes or until cheese is melted.