I would paint window trim and wainscoting under windows the same color as your corner cupboards.

You could do a valence to add some softness/finishijg at the top of the windows while preserving your view.

How about roman shades? I had some custom made by JC Penny and I am very happy with them.

Bamboo blinds would be good for your kitchen style.

or valances

I like Jeanne Caldwell’s idea, but not sure if baseboard heaters like that can be painted. The inside mount valance is cute too. Keep it simple.