Cook the udon noodles according to package instructions. Drain and rinse under cold water to stop the cooking process. Set aside.
In a mixing bowl, combine the creamy peanut butter, soy sauce, rice vinegar, sesame oil, sriracha, honey (or maple syrup), minced garlic, and grated ginger. Whisk together until smooth and well combined. If the sauce is too thick, add a small amount of warm water to reach your desired consistency.
In a skillet over medium heat, add the snap peas and red bell pepper. Sauté for about 3-4 minutes until they are tender-crisp.
Add the cooked udon noodles to the skillet with the vegetables. Pour the peanut sauce over the noodles and toss everything together gently until the noodles and veggies are evenly coated in the sauce.
Cook for another 2-3 minutes, heating everything through while stirring occasionally.
Remove from heat and transfer the spicy peanut udon noodles to a serving dish.
Garnish with sliced green onion, toasted sesame seeds, and fresh cilantro leaves.
Notes
Adjust the sriracha to your preferred spice level.