Slow Cooker Mexican Pulled Pork

Name: Slow Cooker Mexican Pulled Pork
Ingredients: 2 1/2 to 3 pounds boneless pork loin roast; 1 medium onion, thinly sliced; 2 cups store-bought or homemade barbecue sauce; 1/2 cup salsa; 2 tablespoons chili powder; 1 teaspoon ground cumin; 1/2 teaspoon garlic powder; 1/2 teaspoon oregano; 1/4 teaspoon freshly ground black pepper; 1/8 teaspoon ground red pepper, or to taste; 1/2 teaspoon salt; 1 small green bell pepper , cut into strips; 1 small red bell pepper, cut into strips; 1 tablespoon vegetable oil; 10 (8- to 10-inch) flour tortillas