Different lists online list peas differently, some acidic, some alkaline. David Wolfe in his YouTube video on alkalizing the body says, in general, that seeds, roots and muscle (all meats) are acidic. Peas are a seed. He says specifically that they are acidic. Rice is also a seed and acidic, again mention specifically by Wolfe.
We don't need to avoid these foods entirely because we need to balance alkaline with acid. If you're eating lots of alkaline foods then a few walnuts or a serving of peas is fine.
You can get too alkaline. It's just that the standard American diet is so extremely acid.