You can just concat the values using +
<a ng-click="$navigate.go('#/path/' + obj.val1 + '/' + obj.val2)">{{obj.val1}}, {{obj.val2}}</a>
I am sure the code you posted is a simplified example, if your path building is more complex I would recommend extracting out a function (or service) that would build your urls so you can effectively write unit test.