As you have probably discovered, there is no easy way to dynamically add UI nodes to your Dashboard flows. However, you can dynamically generate some basic html elements using ng-repeat inside a ui-template node, iterating over an array of all the data and displaying it. That is basically what ui-table is doing (iirc), and there are several examples in this forum that shown how to iterate over array of images, for example.
But it sounds like you would like to select 1 building out of the list of 100(!) -- so best to have a way to search that list. If you know the max number of sensors in any building will be 10, then you can build a single Dashboard page that shows all 10 sensor types with their charts and gauges. Then you use the building selection list to trigger a flow that pulls only the 10 readings for that selected building. Pass that data to your dashboard, and configure the UI nodes to pull the data by type (e.g. temperature, humidity, utitily usage, whatever). This gives you a way to show all buildings, one at a time, without making a custom dashboard for each.
Here is another similar thread that also mentions the use of the uibuilder node to provide a more dynamic UI app. Although that type of solution is only practical if you have some experience building html/css/js based web apps.
