If you have root, it's pretty easy to make tasker launch an app, wait, emulate a touch at specific point in screen, wait , tap etc. So as long as the position that needs to be tapped within the app is predictable, you might be able to do it....depends on interface complexity as codesplice mentions
http://www.pocketables.com/2013/07/how-to-emulate-touch-input-using-tasker-and-root.html
I used it today to create a task that launches Google Keep, waits for X seconds (for the app to load), and then "taps" the mic icon within Keep to begin recording. So I can dictate notes on the fly (for example when driving) by launching my task. Better than Google Now "note to self" because
1-did not require internet
2-Keep saves the audio recording right along with the voice transcription, so you can listen to it later if the transcription is hard to decipher (due to occasional incorrectly transcribed words).
When I have more time later, I review my stored note, delete the recording, share to Gtasks where I assign it a category and a reminder time if needed.
X has to be around four seconds on my S4 unless I set Keep to be "always resident" using xposed "app settings" module...then can be 0.5 seconds
