In a medium bowl, combine the sausage and half of the scallions; season with salt and pepper. Shape into 16 meatballs.
In a medium saucepan, bring 3 cups water to a boil. Stir in the rice, cover, lower the heat and simmer for 15 minutes. Using a fork, stir in the sesame seeds.
Meanwhile, in a large nonstick skillet, heat the oil over medium heat. Add the meatballs and cook, turning, until cooked through and browned, about 15 minutes.
In a small saucepan, combine the pineapple, pineapple juice, chipotle and cumin; cook over medium heat until reduced by half, 10 minutes. Pour the sauce over the meatballs; stir in the cilantro and remaining scallions. Serve on top of the rice.