postgres json: How to query map keys to get children

I'm new to postgresql and I am having trouble finding an example of how to query the following:
{ "Skill": { "Technical": [ { "Name": "C#", "Rating": 4, "Last Used": "2014-08-21" }, { "Name": "ruby", "Rating": 4, "Last Used": "2014-08-21" } ], "Product": [ { "Name": "MDM", "Rating": 4, "Last Used": "2014-08-21" }, { "Name": "UDM", "Rating": 5, "Last Used": "2014-08-21" } ] } }
In short I struggling with understanding how to query through maps without having to be explicit about naming each key.
I have a query that does the following, though it seems a bit much to have to do...
Select 'Technical' as SkillType , json_array_elements(ResourceDocument->'Skill'->'Technical')->>'Name' as SkillName , json_array_elements(ResourceDocument->'Skill'->'Technical')->>'Rating' as Rating , json_array_elements(ResourceDocument->'Skill'->'Technical')->>'Last Used' as LastUsed FROM testdepot.Resource UNION ALL Select 'Product' as SkillType , json_array_elements(ResourceDocument->'Skill'->'Product')->>'Name' as SkillName , json_array_elements(ResourceDocument->'Skill'->'Product')->>'Rating' as Rating , json_array_elements(ResourceDocument->'Skill'->'Product')->>'Last Used' as LastUsed FROM testdepot.Resource
I am trying to find a way to do this in 1 query that allows containing all keys of a map.In this case Product and TechnicalSomething like:
Select 'Product' as SkillType , json_array_elements(ResourceDocument->'Skill'->*)->>'Name' as SkillName , json_array_elements(ResourceDocument->'Skill'->*)->>'Rating' as Rating , json_array_elements(ResourceDocument->'Skill'->*)->>'Last Used' as LastUsed FROM testdepot.Resource