Cut the sugarcane half, forming 2 (6-inch) canes. Then, cut the sugarcane lengthwise, into quarters, forming 8 skewers, about 1/8 of an inch thick.
Thread each piece of chicken onto a single sugarcane skewer. Repeat the process with rest of skewers and chicken. Place the skewers in a shallow bowl.
In a small bowl, combine the oil and garlic, mix well, and then pour the mixture over the chicken skewers let to marinate, covered and refrigerated, for at least 2 hours.
Meanwhile, make the sauce. In a saucepot, over medium heat, pour a little oil. Saute the onion, peppers, and garlic slowly, cooking for about 10 minutes. Then, add the chicken stock, green plantains, and peanuts. Cook this mixture until the plantains have become tender, about 20 minutes. Remove the pot from the heat, and then, using an immersion blender or a food processor, puree the sauce.
Preheat a grill or the broiler.
Grill the chicken skewers until they are firm to the touch and cooked through, about 3 minutes per side. Serve with a side dish of the Sango Sauce, for dipping.