Combine the dressing ingredients in jar and shake vigorously (or in bowl and whisk well). Cook the orzo in large pot of boiling salted water, stirring occasionally, about 8 minutes. Add the corn and cook about 2 minutes more or until the pasta is still firm to the bite. Drain and place in large bowl. Add half the dressing and toss to coat. Cool a bit, then add the remaining ingredients and the rest of the dressing and toss to coat. Cover and chill until ready to serve.