You have a little zoo under those leaves. The flying white insects are white fly. The long curly lines on the leaf are leaf miners and I think you have spider mite damage too judging by the stippling of yellow areas where the plant juices have been removed by insect activity.
You could do nothing as you only want the beans to harvest or spray a mixture of dish soap and water on the underside of the leaves two or three times at four to five day intervals.
The leaf miners cannot be treated with soap but they are not significant.
Edit: White fly is the most likely pest that fits the description but they could be something else. Either way spraying with soap and water will control them until harvest time.