Asian shares began the week on the back foot on Monday after a downbeat session on Wall Street, while the euro skidded to a fresh 12-year low on divergent monetary policy paths between the United States and the euro zone. Oil continued to tumble, with U.S. crude dropping more than 2 percent to a six-year low, after the International Energy Agency said on Friday that the global supply glut is growing and U.S. production shows no sign of slowing.