Wash and dry all produce. Adjust rack to upper position and preheat oven to 450 degrees. Thinly slice scallions, keeping greens and whites separate. Mince garlic. Place half chickens skin-side up on a foil-lined sheet. Rub with a large drizzle of oil. Season with salt and pepper. Bake in oven for 35 minutes.

Heat 2 TBSP oil in a medium pot over medium heat. Add half the garlic and cook, stirring frequently, until crisp, 3-4 minutes. Remove from pot with a slotted spoon and transfer to a paper towel-lined plate.

Increase heat under pot to medium-high and add scallion whites. Cook, tossing, until softened, about 1 minute. Add rice and toss to coat. Stir in 11/2 cups water and a large pinch of salt. Bring to a boil, then cover, lower heat, and reduce to a gentle simmer. Cook until tender, about 15 minutes.

Heat a drizzle of oil in a small pan over medium-high heat. Add remaining garlic and cook until fragrant, about 30 seconds. Stir in soy sauce, vinegar, ketchup, 2 TBSP water, and 1/4 cup sugar. Let simmer until slightly thick and sticky, 4-6 minutes. Season generously with pepper, then remove from heat. TIP: If glaze becomes stiff, stir in a splash of water.

Remove chicken from oven after 35 minutes. Adjust rack so that it is about 8 inches from broiler; heat broiler to high. Return chicken to oven and broil until browned, 8-10 minutes. Remove from oven and brush all over with half the glaze. Return to broiler and continue broiling until glaze is set, about 1 minute. Let chicken rest 5 minutes after removing from oven, then cut each half between breast and leg to divide into two pieces.

Place green beans in a medium bowl and add a splash of water. Cover with plastic wrap and poke a few holes in wrap. Microwave on high until tender, about 2 minutes. Divide rice and green beans between plates. Arrange chicken on top. Drizzle with remaining glaze. Sprinkle with crisped garlic and scallion greens.