Hello Lindsey,
Thanks for reaching out. Out of the box, this feature is not available in Method. The reason why we do not have this in the first place is to avoid mass delete of the data. Because if you delete the activities it is a hard delete and you might lose that data.
But if you would still like to add that feature in Method, you would need to customize your ActivityList screen in Method.
What you can do in this case is, add a button on the screen and assign a delete action on it.
You would need to Loop through the Grid where the rows are selected and delete the records from the table. That should help you accomplish in what you are looking for.
- Inder