Do they share a room? Does Jake go to bed on his own, or do you have a repertoire of tricks to get him to go to sleep?
When Lyra (she's four) gets wound up after dinner, it's usually because she's getting more tired (vicious cycle). In the past, if I let her stay up past eight, she wouldn't go to sleep some nights until eleven!
So now we have a very strict bedtime routine: dinner is at six, then bathtime, then brushing teeth, stories, then bed at 7:30. For whatever reason, this works like a charm, and we haven't had any bedtime-related hassles for months.
But with two kids, it must be so much harder! Could you put off dinner until after the kids have had fifteen/twenty minutes to rough house with their dad once he gets home? If they could get that energy out of their system, they might be more relaxed and focused at dinner (alternately, this could backfire - depends on the kids!). But it's important that playtime doesn't extend into dinnertime - once dinnertime comes it's time for everyone to chill out. My daughter's a total wiggleworm at dinnertime but a reminder that I'll count to three (warning for a timeout) usually gets her to focus on her food.
As far as bedtime itself goes, could you and your husband each get one of the children ready for bed? If you always put Jake down about a half-hour before he puts Sammy to bed (whoever has the hardest time going to sleep should probably go to bed first so they won't disturb the other one), that could inject some serious routine. With my daughter, always knowing what's about to happen really helps - it seems that when kids think that anything could happen, they're much more likely to bounce off the walls.
Just some ideas.
Let us know how it's working!