Heat olive oil in a nonstick skillet over medium-high. Add green onion and vegetables or spinach, and cook, stirring constantly, until vegetables are heated through or spinach wilts, about 1 minute.
Add egg and salt. Cook, stirring often, until egg is scrambled and nearly cooked, about 1 minute. Add rice and lemon juice, and cook, stirring constantly, until warm, about 1 minute. Sprinkle cheese on top. Spoon evenly into pita half.