I'd like to be able to send an Echo a command as if I've said it.
for example, i have a Ring doorbell, i'd like to be able to say "Alexa, show the front door" virtually, so if there's motion or the doorbell rings, it show's the front door.
clearly this is something Alexa and Ring should just do, but it doesn't and really it's an example, to see if i could trigger playing a radio station, or something, as the Hubitat Alexa App seems a little limited.. unless i'm missing something!
You basically want to have Hubitat trigger an Alexa Routine. The simplest way to achieve this without any custom software is to use a virtual contact sensor device in Hubitat, expose that via the Amazon Echo Skill App, and then use it within Alexa as the trigger for an Alexa Routine. You can use Rule Machine to set the virtual contact sensor to 'open' and then a few seconds later back to 'closed' so it is ready for the next time you want to use it.
However, you will be limited by the capabilities that are available within an Alexa Routine. Not sure you can do everything you want, unfortunately.
The other crazy option is to use a Text to Speech device, like an IKEA Symfonisk speaker, next to an Amazon echo and have Hubitat send the exact phrase you want to the speaker. This will wake up Alexa and she'll perform the task you want. It's a kludge, for sure...but works! 
Thanks for this, i did think about the routine, but that's not possible with the Ring for example.. however the speaker may work!
I think we need someone to write a more comprehensive Echo app, I known when I played with OpenHAB for a while (2 days lol), I could make my Echo's do thing, like switch on the radio etc.
Echo Speaks will allow you to trigger a radio station and more.
As @Kev said, take a look at Echo Speaks
Adding solely for the historical record, that we former Vera (and current ezlo) hub users had access to this very tool by a couple of methods. First, ezlo was/is trotting out a feature they call VOI which allows their new hubs to silently send Echo devices commands as though you spoke them. It's uncannily good -- when it works.
The other method involves a 3rd party plug-in called AlexaVera, still in beta, which leverages some code cobbled together in 2020 which accomplishes the same thing. Unfortunately, it's kludgy, is prone to breaking as Amazon is constantly changing or limiting the API, and requires some finesse to get the required cookie file into place for the app to work. But when it works, it's fantastic.
Both of these open up avenues which I think have largely gone under the radar for even the most seasoned HA enthusiast. For example, without resorting to IFTTT, so long as your various HA ecosystems interoperate with Alexa, you can "ask" her to perform actions on devices the Hubitat normally would not address.
Example: Sending "Turn on my workshop air conditioner" works as expected even though the A/C unit normally requires the LG mobile app. Although LG withdrew IFTTT connectivity last year, they still offer a Smart Skill on the Echo platform, so VOI™ and AlexaVera can work this magic for you.
As has likely been voiced a number of times here on the forum, Hubitat most definitely needs this same feature and pronto, if it doesn't already have it in late 2021.
UPDATE: The solution all along is/was the amazing user app [BETA] Echo Speaks V4!
Download the Hubitat app
