Undoing the flavor effects of baking soda in cooking
You cannot remove a flavor that's been added to a dish once. There are very few exceptions to this, and I would say this isn't one of the exceptions.
You will find people telling you that baking soda is neutralized by acids. While chemically, baking soda can react with an acid, I would say that this won't help you here:

baking powder is a combination of baking soda and acid and I personally easily notice the metallic taste in anything made with baking powder. So the reaction products don't taste much better than the baking soda itself.
a tomato sauce likely also has fat. Some of the unpleasant soapy taste of adding baking soda to food happens due to its reactions with fat, and I don't think that the products of this reaction will react with acid.
your sauce has quite some acid already, through the tomatoes (and possibly more, if you used canned tomatoes or more ingredients which add acid, like vinegar). If acid was enough to prevent the bad taste, it would have happened already.

So, if you want to enjoy the effects of baking soda, you generally also have to live with its taste.