You are almost there. Coax is mostly a URL-path currying API with a little bit of knowledge about changes feed etc. So for your use case you want to do something like this:
// just for example
var database = server("my-database")
database.get(function(error, data){
})
database.get("foobar", function(error, data){
})
// note the array
database.get(["foobar", "baz"], function(error, data){
})
// still an array, with query options
database.get(["foobar", "baz", {"x" : "y"}], function(error, data){
})
It looks like the uri and qs parameters you are using are the API to mikeal's request library, which hoax uses, but doesn't share the same API.
Hope that helps!
Chris