Wash and dry all produce. Trim, then thinly slice scallions, separating greens and whites. Mince garlic. Trim any strings or tough ends from snow peas. Drain pineapple, reserving juice. Heat a drizzle of oil in a small pot over medium-high heat. Stir in rice, scallion whites, and half the sesame seeds. Cook until fragrant, about 30 seconds.