Preheat oven to 425°F.
In a small bowl, whisk together 2 tbsp red curry paste and about ¼ cup coconut milk to create a thin, paintable sauce. Adjust consistency with more coconut milk if needed.
Combine green onion, ginger, garlic, the remaining coconut milk, and tamari in the bottom of a roasting pan.
Place the chicken on top of the aromatics in the pan.
Baste the exterior of the chicken with the curry sauce. Pour any remaining sauce into the pan with the coconut milk mixture.
Roast until the internal temperature reaches 160°F in the thickest part of the breast (approximately 1 hour 5 minutes for a 4lb chicken and 1 hour 15 minutes for a 5lb chicken).
Baste the chicken after 20 minutes of roasting and rotate the pan to ensure even browning. Tent with foil if the skin starts to darken too quickly.
Remove the chicken from the oven and let it rest for 15 minutes.
Strain the aromatics from the pan sauce.
Shred the chicken into large pieces and return it to the pan with the coconut curry sauce. Toss well to coat.
Serve the shredded chicken over cooked white rice, garnished with chopped green onion and freshly squeezed lime wedges.
