Cook pasta according to package directions; drain and set aside.
Brush both sides of flank steak evenly with olive oil, and sprinkle with salt.
Grill steak, covered with grill lid, over medium-high heat (350° to 400°) 8 to 10 minutes on each side or to desired degree of doneness. Let stand 10 minutes before slicing. Cut diagonally across the grain into thin strips.
Heat 1/2 cup Dried Tomato-Basil Pesto in a large nonstick skillet over medium heat. Add beef strips, and cook, stirring often, 2 to 3 minutes. Add spinach, and cook, stirring often, 3 minutes or just until wilted. Add cooked pasta and remaining 1/2 cup Dried Tomato-Basil Pesto, and cook, stirring occasionally, 2 minutes or until thoroughly heated. Sprinkle with ground pepper and red pepper, and serve immediately.