Tiny black bugs
Your picture is fuzzy but I sent it to a beetle expert to at least identify the family so my response will be relevant for you problem. Meanwhile, have you noticed whether these insects are also in cupboards where you might have flour or other grains stored? Check you containers to determine whether you see the insects in those locations. Some flour beetles (several species) are pests on stored grains or flour. However, I can't quite tell if the picture is a flour beetle.