1. Prepare rice according to package directions. Let cool.
2. Meanwhile, process cilantro and next 4 ingredients in a blender 10 seconds or until smooth. Cook ground sirloin in oil in a large skillet over medium-high heat, stirring occasionally, 5 to 7 minutes or until meat crumbles and is no longer pink. Add green onions and ginger, and cook stirring often, 3 minutes. Add spinach and salt; cook, stirring constantly, 1 minute or just until spinach is wilted.
3. Toss lettuce, rice, and beef mixture each with 1/4 cup cilantro mixture. Divide lettuce, rice, and beef mixture evenly between 4 individual serving plates. Garnish, if desired.