In large bowl, mix vegetable oil, taco seasoning mix, cumin, coriander and salt. Add pork, and toss to coat; pour into 5-quart Dutch oven. Place onions and garlic on top of pork. Pour in water, orange juice and lime juice. Heat to boiling over high heat. Stir; reduce heat to medium-low, and simmer uncovered 2 to 3 hours, stirring occasionally, until pork is tender.