Place zucchini in a colander over a plate; sprinkle with 1 teaspoon salt and toss. Let stand 30 minutes. Rinse and drain well; blot dry with paper towels. Meanwhile, separate eggs; let stand at room temperature 30 minutes. Grease a 2-1/2-qt. souffle dish; dust lightly with flour., Preheat oven to 350°. Place corn in a large saucepan; add water to cover. Bring to a boil. Reduce heat; cook, covered, 3-5 minutes or until crisp-tender; drain. Cool slightly. Cut corn from cobs and place in a large bowl., In a large skillet, heat butter over medium-high heat. Add green onions and zucchini; cook and stir until tender. Stir in flour, pepper and remaining salt until blended; gradually stir in milk. Bring to a boil, stirring constantly; cook and stir 1-2 minutes or until sauce is thickened. Add to corn; stir in cheese., Stir a small amount of hot zucchini mixture into egg yolks; return all to bowl, stirring constantly. Cool slightly., In a large bowl, beat egg whites on high speed until stiff but not dry. With a rubber spatula, gently stir a fourth of the egg whites into zucchini mixture. Fold in remaining egg whites. Transfer to prepared dish. , Bake 45-50 minutes or until top is puffed and center appears set. Serve immediately.