Combine coriander, chilies, peanuts, lime juice, oil, mirin, and sugar in a food processor.

Blend until the mixture is roughly chopped, forming a vibrant green sauce.

Place half of the coriander mixture in a bowl with the chicken strips.

Toss the chicken to ensure it's evenly coated with the marinade.

Heat a large frying pan or wok over medium heat.

Add the marinated chicken to the hot pan and cook until it is cooked through and lightly browned.

In a separate bowl, combine the blanched udon noodles, sliced green beans, and the remaining coriander mixture.

Thoroughly mix the noodles and vegetables with the coriander sauce to ensure they are well coated.

Divide the noodle and vegetable mixture into serving bowls.

Top each serving with the cooked spicy coriander chicken.

Serve immediately and enjoy the flavorful combination of spicy chicken and fresh noodles.