In a medium pot, fitted with a steamer, add 2 C water, 1 T pureed ginger, lemongrass, juice of two limes and two cloves crushed garlic.
Place the chicken in the steamer, cover and cook for 10 - 15 minutes or until chicken is just cooked through. Shred the chicken and set aside.
In a medium bowl, whisk together the scallions, Tamari sauce, 2 T pureed ginger, rice vinegar and sesame oil. Set aside.
Bring 6 C of water to a boil in a medium stock pot.
Cook the Udon noodles for 4 minutes. Drain, return noodles to the pot and toss with 1 T of the neutral oil to prevent sticking.
In a large wok, over medium-high heat, warm 2 T of the neutral oil.
Add the minced garlic and sauté until fragrant, about a minute.
Add half of the scallion mixture, the Udon noodles and shredded chicken. Toss to combine.
Add the eggs and spinach and sauté until the eggs are cooked.
Add the sriracha sauce and remaining scallion mixture and toss to combine.
Serve immediately garnished with cilantro, a squeeze of fresh lime juice and sriracha sauce, if you like it super spicy.