In a bowl, mix the shallot, the 2tablespoons tamari, sugar, fish sauce, lemongrass, oil, chile sauce, and salt. Cut any excess fat from the chicken. Add the chicken to the bowl and toss to coat. Let the chicken marinate while preparing the rice.
To make the ginger rice, in a small saucepan, bring 1½cups (12fl oz/375ml) water, the ginger, and salt to a boil. Add the rice and return to a boil. Reduce the heat to low, cover, and cook for 30 minutes. Turn off the heat and let stand at least 5 minutes. Fluff the rice with a fork, then mix in the tamari.
Meanwhile, prepare a grill for direct-heat cooking over high heat. Remove the chicken from the marinade and add to the grill rack, cover, and cook until springy to the touch and cooked through, about 6 minutes per side.
Divide the rice among 4 warmed plates. Top with the chicken, sprinkle with green onions, and serve right away.