Abby, you will not find much in the way of plans available for something like this because there are so many variations in size, shape, style and other design features. You need to think out want you want first. Do you want something that is basically a ledge along one or 2 walls? a table with a bench on one or both sides of it? bench on one side and chairs on the other?
I don't think that you will find many Louis 14th kitchen nooks, but do you want something that looks Deco, Modern, Shaker or ??? Anything is possible and starting with unfinished furniture or a basic outdoor type picnic table might help you along. What kind of tools and equipment do you have access to?
I'm not trying to put roadblocks in front of you but if you know and can tell us want you want, it's that much easier and better as far as the direction you will get.