When the coals are red and dusted with ash, divide them in two, placing half on each side of the barbecue. Set the grill over the coals and when it is hot, lay the chicken on top of it right over the coals just long enough to get grill marks on the chicken, which will take about 2 minutes. Move the chicken to the center of the grill, Season it generously with salt and pepper, cover and cook for 10 minutes. Turn it and repeat, including the seasoning. The chicken should be golden, and should have an interior temperature of 160F (71C) which will rise to about 165F (74C) as the chicken rests before serving. Remove the chicken from the grill and let it rest for at least 10 minutes.While the chicken is grilling, cook the rhubarb. Whisk together the water and the sugar in a large saucepan. Place it over medium-high heat. Add the birds’ eye peppers and the rounds of ginger and bring to a boil, stirring occasionally. When the sugar is dissolved, fold in the rhubarb and cook, folding gently so the rhubarb and syrup are combined, until the rhubarb softens but doesn’t turn mushy. This will take 3 to 4 minutes. Be very careful to watch the rhubarb, as you don’t want it to overcook. Remove the rhubarb from the heat.