Is there any way I can speed up this large full-table query?
Is there anything obvious I can do to improve this query's performance by adding/tweaking indexes or tweaking the query itself?


Yes.  First make the predicate sargable.

SELECT * FROM 
[Sales].[dbo].[Interaction] 
WHERE Interaction_date &gt;= '20190101'


And then consider partitioning, or a filtered index with included columns.  But even if you have an index that can support this query as a simple seek+scan, sending all the columns to the client takes time.