If you're talking about the editorial:// URL scheme, you can pass a selection parameter to set the cursor position or selection range. editorial://open/foo.txt?selection=5 puts the cursor at position 5, and editorial://open/foo.txt?selection=5-10 selects characters 5 through 10. As far as I can tell, both versions activate "editing mode" (i. e. bring up the onscreen keyboard).
Also, if there's anything that the URL scheme doesn't support, but can be done with a workflow, you can use the command and input parameters to run a workflow with the given input, and use that workflow to do what you need.