(Reuters) -Chipotle Mexican Grill plans to foray into Asia next year by opening restaurants in South Korea and Singapore, as the bowls and burritos maker seeks to expand its global footprint amid easing consumer spending on dining out in key U.S. market. The California-based company will open the restaurants through a joint venture with South Korea-based food company, SPC Group, it said on Wednesday. "With a rapidly evolving dining-out business, fueled by preferences for variety and convenience, expandi ...