i use a large washing up bowl and put a few oinches of water in it and let the soil soak up the water from below. once its wet, i drain the excess water out of them and dig a hole and pop a seed into them.
i find it easy to dip my hand in water and drip the water coming off my fingers over the area the seed is planted in , this keeps the seed area moist but not soaking wet.
with a transplant, i use the soil as it is, transplant into a pot, get some soil tucked down aroyund the newly transplanted plant and then give it a water from on top, but not to run off, just enough to make sure the plant wont go dry