Cut tofu into chunks, and drain on a paper towel. Place starch into a plastic bag, add tofu and shake to coat. Add 3 tbsp oil to medium non-stick skillet and preheat over medium heat. Place tofu into skillet and turn up heat to medium-high. Meanwhile in another pan, sauté onion and garlic until starting to brown. Add the ketchup, honey, Gochujang and water, bring to a boil. Mix to coat tofu with sauce, serve over rice and garnish with thinly sliced green onion tops.