1. Cut zucchini in half lengthwise, then on the bias into 1/4-inch slices and sprinkle with salt and pepper. Heat 1/2 tbsp oil in a large nonstick skillet over high heat and add zucchini. Cook, stirring, until just golden, about 2 min. Remove zucchini, then reduce heat to medium and add polenta to skillet. Cook, stirring, until just heated through, about 4 min.
2. Whisk together vinegar, oregano, sugar, salt and 3 tbsp olive oil. In a large bowl, toss half the vinaigrette with the greens, chicken, zucchini and polenta. Arrange on a platter and sprinkle with blue cheese. Serve with remaining vinaigrette. Makes 4 servings.