Bring a large pot of lightly salted water to a boil. Add the chicken to the pot along with smashed garlic and sliced ginger. The chicken should be completely submerged, but only just. Cover, reduce heat to low and simmer for 40 minutes. Turn off heat and let the chicken cool in the water. Remove chicken from pot and strain the stock. Defat the stock and reserve the fat. Reserve 4 cups of the stock (freeze the rest). When the chicken is cool enough to handle, shred it in small pieces, discarding the skin, bones and nasty bits.

Put the reserved chicken fat in a 2- to 3-quart pot over medium-high heat. When the fat is warm, add the shallots; cook, stirring occasionally, until lightly browned, about 5 minutes. Add minced garlic and rice and cook until lightly toasted, stirring to coat another 2 minutes or so. Add 4 cups reserved chicken stock and bring to a boil, then reduce heat to low and cover; cook for about 18-20 minutes or until rice has absorbed all liquid. Stir in salt and pepper to taste.

Make a sauce of the peanut oil, sesame oil, soy sauce, remaining ginger and half the scallions. Put rice on a large platter and mound the chicken on top of it; put the sliced tomatoes and cucumbers around the edge and sprinkle with the remaining green onions and cilantro. Drizzle the sauce over everything.