In the sprytile build tool, holding down S will snap the 3d cursor to the vertex nearest to your mouse cursor.
You can configure it to snap to vertices or the virtual grid in the workflow panel.
Turning on cursor flow will make the 3d cursor follow along your tiles while you build.
Good point about delete face. In 2.79 Sprytile was integrated with geometry manipulation so you didn't have to exit out of build mode to delete things, but 2.8 changes the workflow so maybe its time to implement a delete shortcut.