Season chicken thighs with salt and pepper. Heat a skillet over medium heat. Place chicken thighs. skin side down. in skillet. Cook until cooked through. and skin is browned and crisp. 14 to 16 minutes. Transfer to a plate and set aside.
Thinly slice the shallot. garlic. and ginger. Finely chop the Swiss chard ribs and stems. and coarsely chop the leaves.
Heat 1 tbsp olive oil in same skillet over medium-high. Add Swiss chard ribs and stems. shallot. and ginger. and cook. stirring occasionally. until softened. about 3 minutes. Add Swiss chard leaves and vinegar.
Cook. stirring until slightly wilted. about 3 minutes. Season with salt and sprinkle with red pepper flakes. Serve chicken with chard. Pour salsa over top and garnish with fresh cilantro.