Toast walnuts and almonds in a skillet over medium-low heat, 4 to 5 minutes. Chop into big pieces and set aside. Pour water and fonio into a medium saucepan. Stir to eliminate any lumps. Add dates. Bring to a low boil, stirring often while crushing the date pieces. Reduce heat to a simmer when dates begin to dissolve. Add 1 cup milk, raisins, and cranberries. Continue to simmer, stirring often, until fonio absorbs all the liquid, about 8 minutes. Divide the porridge into 6 bowls. Serve topped with equal amounts of toasted nuts, blueberries, 6 tablespoons milk, coconut, and cinnamon.