By Sarah Wu KINMEN, Taiwan (Reuters) -Pointing at Xiamen’s skyscrapers across the water from his office, Chen Tsang-chiang recalled how 30 years ago the southern Chinese city was as low-slung as his Taiwanese island of Kinmen. In the following decades, the 68-year-old former politician watched the metropolis of 5 million people rise, while Kinmen’s forests, sorghum fields, and villages saw little change. What the Taiwan-controlled island about the size of Washington, DC, and only some five km (three miles) off China’s coast needs, Chen says, is a bridge to Xiamen – “a connection to an economic…