Dim Sum at Sun Sui Wah Seafood Restaurant in Vancouver, B.C. The style and form of dim sum has evolved and refined over the years. Each region of China offers their own unique specialties but the most popular selections come from Canton and Hong-Kong. During the 70's when Hong-Kong enjoyed an economic boom, the restaurant business flourished as a result. With intense competition, comes the need for improvement and the mobile dim sum cart with burner food warmers were introduced.