Process the chicken by sous-vide. Season the chicken with salt and pepper. Slice one of the garlic cloves very thinly, and put one thin slice on each thigh. Distribute the sage amongst the thighs. Place them in a bag, seal, and sous-vide at 176 F (80 C) for about three hours.
While the chicken is cooking, bring a pot of water to a boil. Put beans in a casserole, with the garlic clove, and sprinkle with the salt. Pour sufficient water over the beans to cover by an inch or so. Put into a preheated 250 F oven. Bake till the beans are tender, stirring every half hour or so. Add additional water as needed.
Drain the chicken, reserving the liquid.
In a pan large enough to hold all the chicken, saute the onion and remaining garlic (minced) in some olive oil (or chicken fat) till tender. Add the chicken, and deglaze pan with the wine. Reduce till almost dry.
Drain the beans. Add the drained beans, remaining sage, diced, and the chicken stock to the chicken. Stir in the tomato paste (you can add the paste to the stock before adding to the pot if you want). Stir and season with salt and pepper.
Cook till proper consistency (your choice). Add minced parsley and serve.