1: a target can decide to willingly fail it's saving throw.
and can also be tricked to do so: "yea, trust me in going to heal you not poison you" - -cure light wounds also has a save.
2: i think your mixing casting time and duration a bit. so lets go for a long walk:
castings spell with charges that can be held allow a free touch attack (auto hit on willing target) on the same round that it is cast. it's a free action that can be done anytime during the caster's turn. but not in mid action.
so for example:
in the 1st round he can cast a touch spell like cure light wounds, then use his move action to move then use the free action to touch his target. if it's undead and it doesn't want to take damage (mostly won't want) the caster need to land a touch attack and the undead get a save for half. if it's alive and want to be healed - the caster doesn't need to roll to hit and the target doesn't need to save for half.
if by the end of the 1st round he didn't discharge the spell (by touching a target or casting an other spell, quickened for example) the caster can hold on to the charge. -depend on the spell most have a number o charges and no duration .some have duration. in the later it can be held up to the duration in the former it can be held indefinitely within reason. touching and delivering the charge after the 1st round require a touch attack as a standard action (targeting touch ac) or as part of an unarmed attack (as a normal attack or a part of full attack or the like. targeting normal ac).
in any case. if there is a duration for the spell once it hits. the duration clock down from that moment (which should be on hte caster's turn unless he held the charge and discharged on some1 else's turn. like with an attack of opportunity)