Could I substitute tomato paste for fresh tomatoes? Or would canned tomatoes make more sense? If the answer is yes to either of these, I'd love a...

While I've never made this specific recipe, as an old fogey I am well acquainted with the flavor of fresh tomatoes, canned tomatoes and tomato paste.

My choice to replace fresh tomatoes would be canned whole peeled tomatoes. I find tomato paste to be highly concentrated, not very similar to fresh tomatoes, but I don't know how your taste buds respond.

As to the amount, I'd say about a half of a standard 14 oz. can. I rarely cook from recipes, so I would add what I felt would be most likely to please my own taste buds.

Looking at the recipes and the accompanying photos, the tomato does not appear to be a primary ingredient, it's more there to add some moisture and acidity, so I would refrain from adding a large quantity.

Anyhow, best of luck.