Pour about 3-4 tbsp of water in the pan and immediately cover. Cook just till the broccoli turns vibrant green, just a few minutes. If you're using snap peas add these just in the last minute before you add your sauces as they don't need long to cook. The veggies should still be crunchy at this stage but will continue to cook for a couple minutes as you make the sauce so don't cook too long. Remove the lid and add the soy sauce, mirin and chili sauce. Mix then immediately add the cornstarch and water and mix quickly. Continue to mix till the sauce is thickened. Remove from heat and add the sesame oil and seeds. Then add in the noodles, mix well, add more soy sauce as needed and serve. Top with more sesame seeds and some chili sauce of choice.