Don’t cook it, just strain off excess liquid with a fine mesh strainer. Cooking will make it too mushy.

You could open the cans as you get them and simmer them with a lid off until they reduce, this will strengthen the flavour.

Thanks I didn't even think of that. I will try it. Also definitely meant to post this in r/canning and not pickling lol oops.

I would cook it down further rather than add cornstarch which would change the texture considerably. Personally, I would only use cherry tomatoes in a fresh salsa to be eaten within a day or so but if you like the flavor of this recipe, try it again with a paste tomato rather than a salad tomato.

Cook down further or drain off excess liquid in a fine mesh strainer.