Boil water and cook udon noodles according to package instructions until al dente, then drain and set aside.
Slice the chicken breast into thin strips and season with sea salt and black pepper.
Heat toasted sesame oil in a large skillet or wok over medium-high heat.
Add the chicken strips to the skillet and sear until golden brown and cooked through, about 5-6 minutes.
Remove chicken from the pan and add the broccoli, carrots, and sugar snap peas, sautéing until crisp-tender.
Stir in the minced garlic and grated ginger, cooking for 1 minute until fragrant.
Whisk together tamari, rice vinegar, and sriracha in a small bowl to create the stir-fry sauce.
Return the chicken and cooked noodles to the skillet, pouring the sauce over the mixture.
Toss everything together for 2 minutes until the noodles are well-coated and heated through.
Garnish with sesame seeds before serving hot.