Heat oil in a skillet over high heat. Add ribs. Cook, turning occasionally, until browned on all sides, 6 to 8 minutes.
Place browned ribs in a 3-quart slow cooker.
Place soy sauce, light soy sauce, rice wine, onion, orange juice, garlic, ginger, and jalapeno into a blender. Cover and blend until combined. Pour sauce over the the ribs in the slow cooker. Cover and cook on High until meat pulls away easily from the bone, 3 to 4 hours.
Set oven rack about 6 inches from the heat source and preheat the oven's broiler. Place ribs on a baking sheet or roasting pan.
Bake ribs under the preheated broiler until nicely charred but not burned, about 5 minutes. Garnish with scallions.