Cook bacon in a skillet over medium heat until crisp, about 5 to 7 minutes. Transfer to a paper towel-lined plate to drain.
Combine kidney beans, red beans, peaches, onion and cooked bacon in a slow cooker. In a small bowl, mix together tomato sauce, preserves, molasses, vinegar, chili powder, dried mustard and salt. Pour over bean mixture and stir well. Cook on HIGH for 3 hours.