While the Brussels sprouts roast, in a medium pan (nonstick, if you have one), heat 1 teaspoon of olive oil on medium-high until hot. Add the ginger; season with salt and pepper. Cook, stirring constantly, 30 seconds to 1 minute, or until fragrant. Add the clementine, sugar, remaining vinegar and 1⁄2 cup of water (be careful, as the liquid may splatter). Cook, stirring occasionally and smashing the clementine with the back of a spoon, 7 to 9 minutes, or until thoroughly combined. Turn off the heat; season with salt pepper to taste. Transfer to a bowl. Rinse and wipe out the pan.