With 2d sprites you'd have to draw them lit from different sides I suppose.
It may be enough to just have a gradient sprite over the flash with the additive, screen, or lighten blend mode though. You could even give the impression of a brighter flash by darkening everything underneath first. With more layers, or the drawing canvas you can mix and mask multiple light gradients with a sprite with blend modes. It's just something you'd have to fiddle with. If you find any information about how to do such a thing in photoshop or something the ideas may transfer.
For more advanced lighting you could look into a normal map lighting effect. There is a built in one where you place the sprite, then a sprite on top to use as a normal map, and give the effect to that and provide the light location as parameters. There is also a third party effect that has more features. Anyways, the busywork to drawing/generating the normal maps of the sprites.