MANHATTAN BEACH By Joe Perrone, Jr.        I first saw Manhattan Beach in my youth, With its old couples strolling the sand,      Smiling faces advertising their love. I watched as young mermaids,      Waded bravely into the water, Wearing oversized tee shirts turned inside out,      To hide the names of high schools, That everyone knew they went to, anyway.        In the public lockers, men with…