If you want to tour on $15 a day for 10,000 miles, I suggest you revisit your plan to leave behind cooking utensils. You've already got a whole slew of suggested stuff that is highly nutritious but needs some sort of cooking. Like the dandelions and couscous, and bread and so the list goes.

I have found cooking oats to be a great source of cheap nutrition. But you still might need to cook them.

One of the things about extended touring and being intent on keeping to a short list of "simple foods" is that they become mighty boring after a relatively short time.

You really should consider thinking about the types of food that will be part of the culture of the areas you intend to visit, assuming that those areas are in different countries.

I also would suggest you seriously consider taking a big bottle of vitamin tablets.