Spicy Tomato-Basil Shrimp Skewers

In a medium bowl, combine 1/4 cup olive oil, tomato sauce, vinegar, basil, garlic, cayenne pepper and salt. Add shrimp; stir to coat. Cover and marinate in refrigerator 30 to 60 minutes. 

If using bamboo skewers, soak skewers in water for 30 minutes before using.

In a bowl, combine peppers squares and onion wedges. Add remaining 2 teaspoons oil, turning vegetables carefully to coat thoroughly. 

Starting and ending with shrimp, thread shrimp, orange peppers, onion and yellow peppers on skewers. Drizzle remaining marinade over skewers. Grill for 4 to 5 minutes per side or until shrimp are opaque.