Combine marinade and dressing ingredients in a small bowl. Marinate beef and set aside.
Grill steaks and bell peppers until cooked; toast bread slices and rub with garlic.
Slice steak thinly; dice peppers. Layer ingredients in glasses: bread, spinach, peppers, steak, olives, cilantro, and dressing. Top with cheese and garnish.
Notes
Ensure steaks are cooked to desired doneness for best flavor.