Tiny black fleas are just like any other fleas. They usually are seen in the bathroom and kitchen. Keep your bathroom clean by using a disinfectant and never accumulate garbage in the kitchen. As far as possible keep the rooms clean.
They are called springtails, they have like a little coil on their thorax which enables them to "spring", so hence the name springtail. They are prevalent in areas where moisture and humidity are very high. Check all traps and drains to make sure there is not standing water, or moisture able to seep through.