Bring beans, garlic, coconut milk, and 2 cups water to a boil in a medium saucepan. Reduce heat to low. Cover, and cook until beans are tender but not mushy, 1 hour and 50 minutes to 2 hours.
Stir in 2 1/2 cups water, the rice, scallions, thyme, and 1 tablespoon salt; season with pepper. Bring to a boil. Stir once, then reduce heat to low. Cook, covered, without stirring, until all liquid has been absorbed, about 20 minutes. Let stand, covered, 15 minutes. Fluff mixture with a fork, and season with salt and pepper.