Duane ShimogawaReporter – Pacific Business News Friday, February 24, 2012   About 300,000 square feet of retail space is expected to open on Oahu this year, led by Walmart in Kapolei, the Foodland-anchored Kapolei Village Center, Target and Whole Foods in Kailua and a few tenants at Kaoplei Commons. And there’s more in the pipeline.…