Runs can be be deleted from a step by selecting a single run, selecting multiple runs using multi-select (via shift+click), or selecting all runs, and then clicking the delete icon at the bottom of the screen. This will delete the selected runs, but will not delete the resources that were assigned to those runs. Any resources generated by those runs will be deleted but not unassigned from othersteps where they are already assigned.
Connected runs across steps can be deleted by entering flow mode and selecting the run path to delete. Deleting from a run path will delete the connected runs on the selected steps, and all connected runs in between.
WARNING: Deleted runs cannot be recovered.