Skillet Beans and Tomatoes

Combine 1 (10-ounce) package frozen cut green beans, 1/2 cup coarsely chopped onion, 1 teaspoon sugar, 1/4 teaspoon salt, and 1/4 teaspoon pepper in a large nonstick skillet coated with cooking spray. Cover and cook 8 minutes, stirring occasionally. Add 2 medium tomatoes, cut into chunks; cover and cook 2 minutes or until thoroughly heated.