Prep Time 20 min, Cook Time 2 hours 15 min, Ready In 2 hours 35 min
Season duck legs with salt and black pepper.
Heat vegetable oil in a large, deep skillet over medium-high heat; add duck legs, skin side down, and cook until browned, 3 to 4 minutes per side. Remove duck legs and drain all but 1 tablespoon of duck fat from the pan.
Cook onion in reserved duck fat over medium heat until onion begins to turn translucent, 3 to 4 minutes. Add garlic; cook and stir until fragrant, 1 to 2 minutes.
Stir chicken broth, rice vinegar, soy sauce, sambal chili paste, and bay leaves into onion mixture; bring to a simmer. Return duck legs to the skillet, loosely cover, and simmer until duck legs are tender and easily pierced with a fork, about 2 hours.
Remove cover from the skillet, increase heat to high, and cook until sauce is thick, about 5 minutes; season with salt and black pepper to taste.