Cut beef steak lengthwise in half, then crosswise into 1/8 to 1/4-inch thick strips. Combine 3 teaspoons red curry paste and beef in medium bowl. Cover and marinate in refrigerator 15 minutes.
Whisk coconut milk and remaining 1 to 2 teaspoons red curry paste in small bowl until blended. Set aside.
Heat oil in large nonstick skillet over medium-high heat until hot. Add 1/2 of beef; stir-fry 1 to 3 minutes or until outside surface of beef is no longer pink. (Do not overcook.) Remove from skillet. Repeat with remaining beef. Season with salt, as desired; keep warm.
Pour coconut milk mixture into same skillet; bring to a boil. Reduce heat; simmer 3 to 5 minutes or until slightly thickened, stirring occasionally. Add vegetable blend; bring to a boil. Reduce heat; cover and simmer 5 to 8 minutes or until vegetables are crisp-tender, stirring occasionally.
Return beef to skillet; cook and stir until beef is heated through, about 1 minute. Serve over rice, if desired.
Nutrition information per serving: 318 Calories; 180 kcal Calories from fat; 20 g Total Fat; 13 g Saturated Fat; 4 g Monounsaturated Fat; 49 mg Cholesterol; 214 mg Sodium; 5 g Total Carbohydrate; 1.7 g Dietary Fiber; 28 g Protein; 3.8 mg Iron; 7.8 mg Niacin; 0.6 mg Vitamin B6; 1.4 mcg Vitamin B12; 5.2 mg Zinc; 32.3 mcg Selenium;