Heat oil in 4 1/2- to 5-quart Dutch oven over medium-high heat. Cook onions and garlic in oil 4 to 5 minutes, stirring occasionally, until onions are softened.
Stir in salt, cumin, pepper and pork. Cook 6 to 8 minutes, stirring frequently, until pork is lightly browned.
Stir in chipotle chili, adobo sauce and tomatoes. Heat to boiling; reduce heat to medium-low. Cover and cook 35 to 40 minutes, stirring occasionally, until pork is no longer pink in center.