Make the quick pickles. Place the red onion, carrot and zucchini in container. Heat the sugar with half of the water until dissolved. Add the remaining water, vinegar, and a pinch of salt and pepper. Pour over the vegetables and set aside.
Make the Korean chile-garlic sauce by combining all ingredients in a saucepan over medium heat. Simmer for 2-3 minutes until thickened slightly. Remove from heat.
Cook the udon noodles according to package instructions. Toss with Korean chile-garlic sauce.
Divide noodles into serving bowls. Top with pickled vegetables, scallions, and sesame seeds.
Chef Tips!
Make it your own by adding your favorite toppings. Try kimchi, soft-boiled egg, fried garlic, roasted chicken or pork, or roasted mushrooms.