Place the chicken breasts on the bottom of the slow cooker. Mix together the barbecue sauce, soy sauce, lime juice, ginger, jalapeno, and garlic cloves in a bowl then pour over the chicken. Add the onion and pineapple. Cook on low 5 to 6 hours or high for 2 to 3 hours. Remove chicken and shred. Return to slow cooker and cook on low for another 15 minutes.