I found some success using Google Flights "explore map" tool. Put the destination in and then look to see where low prices pop up.

If your dates are firm, you may have to hover over the bar graph to the left to see if your date pairs are included or if they are unfortunately found in one of the "higher" bars on the graph, rather than the lower ones where the great price was found.

I have no idea if you can limit the map to a certain airline or alliance. I just started playing with this a few days ago and quite by accident.

Hope it helps!