Remove skin from chicken & season lightly with the salt, pepper, Cajun seasoning and garlic powder. Pat seasoning into chicken and place into the slow cooker. Whisk together the brown sugar, pineapple juice & soy sauce; pour around chicken. Cover and cook on low for 5 to 6 hours, depending on the size of the chicken. Use a wide spatula to remove the chicken from the slow cooker to a platter & loosely tent with aluminum foil; set aside to prepare the glaze.
Turn cooker to high until mixture comes to a boil, or transfer to a saucepan for the stovetop. Whisk together the water & cornstarch until there are no lumps. Slowly stir into the boiling sauce until fully incorporated & continue boiling for about 3 to 4 minutes or until mixture thickens. Remove from heat and let rest a moment. Brush the sauce over each chicken thigh & serve the remaining sauce at the table.
Note: I also added a few grinds of Rachel Ray’s Perfect Poultry seasoning to the chicken, which contains sea salt, back pepper, onion, sage, rosemary & thyme. I also used low sodium soy sauce.