Can/should I use baking soda when cooking beans?

In his book On Food and Cooking, Harold McGee writes regarding beans and legumes:

Plain salt at a concentration around 1% (10 g/L, or 2 teaspoons/qt) speeds cooking greatly, apparently because the sodium displaces magnesium from the cell-wall pectins and so makes them more easily dissolved. Baking soda at 0.5% (1 teaspoon/qt) can reduce the cooking time by nearly 75%; it contains sodium and in addition is alkaline, which facilitates the dissolving of the cell-wall hemicelluloses.

Basically, you are right that sodium is important, so both salt and baking soda will have effects that speed cooking. (The idea that salting toughens beans or makes them harder to cook has been covered in another question; brief summary -- it's a myth.) Baking soda is even more effective than salt, because it produces an alkaline cooking liquid. Acids slow the cooking and softening of beans, while alkaline solutions will hasten it.

The main drawback of baking soda is that it also affects the taste and texture (as McGee describes it, "an unpleasant slippery mouth feel and soapy taste"). Also, the effects that lead to a faster breakdown of the beans for softening can also result in destruction of a lot of nutrients, as I discussed in detail in a response to a related question on baking soda, beans, and gas.

To me, the drawbacks of baking soda are too great to justify its use unless I had an emergency situation and had to cook beans very quickly. But it can in fact decrease cooking time significantly, so it can be very effective for that goal.

Chick Peas (aka Garbanzo or Gram) are slightly different to other dried pulses, but the cooking is affected by whether they are to be cooked straight or whether they were soaked (from an hour or two to overnight) first.

In the UK a variety of dried peas known as marrowfat peas are sold with a tablet containing bicarbonate of soda (baking soda) to add to the soaking water to "soften" it. They are then cooked to destruction as mushy peas. That is the cooking method of that dish which requires that outcome -- a sort of green soup with lumps in it! But cooking with baking/bicarbonate of soda destroys the thiamin and also makes them too soft for what is usually needed.

The various dried lentil, pea and bean varieties are all going to need different cooking times no matter how they are cooked, but the traditional the way each was treated and cooked represents the smallest energy consumption or fuel cost to time ratio.

In the example of chick peas, soaking in fresh water for an hour or two will usually be sufficient to reduce cooking time by up to 50%. Kidney beans will need an overnight soak and are the only example of a bean I have personally encountered which will never become tender enough to eat if soaking is omitted. (True story, but then I stopped trying after they had been on the stove all day and most of a night!)

The addition of bicarbonate of soda in fresh green beans (also other "greens" such as cabbage and sprouts) was specifically to enhance the colour, or rather to stop the beans turning a grey colour -- usually only a problem if they are being cooked too long. If so much was added to taste of soap, then obviously far too much was added and the beans cooked far too long. If ever using soda for greens, always use a tiny pinch added when the water has returned to the boil. Discard all the water and drain well to serve or add to another dish.

Cooking habits have changed over recent years, as have our tastes. It would no longer be appropriate to serve fresh beans or cabbage which have been boiled hard for half an hour. Which is why some older recipes need editing and "taking with a pinch of salt" (if you will excuse the pun). Salt I will not even mention because of the Seasoned Advice nutrition police who cut any reference to health and nutrition from posts.

For general rules on cooking pulses, I strongly recommend downloading/reading the Guide to Cooking Beans, Chickpeas, Lentils and Peas a pdf file from the Pulse Canada website.

Baking soda in your court bouillon only destroys the cell wall of your vegetables.

Perhaps you can experiment a bit with a two pot approach, cooking the beans in an alkaline solution for only a little while and then straining them and transferring them to a non-alkaline solution (a normal pot of boiling water). Your results may be of value to the community in more of an applied science sort of way compared to the more vaunted book learnin' or academic strain which I for one tend to lean toward in an almost reflex fashion.