Spicy Teriyaki Beef Salad

Ingredients

• 1 cup teriyaki sauce
• 2 tablespoons minced garlic
• 4-1/2 teaspoons sesame oil
• 1 teaspoon crushed red pepper flakes, divided
• 1 teaspoon cayenne pepper, divided
• 1 pound beef top sirloin steak, cut into thin strips
• 1 medium ripe avocado, peeled and chopped
• 1 cup chopped cucumber
• 1 cup soy sauce
• 1/2 cup red wine vinegar
• 1 tablespoon sugar
• 1 large portobello mushroom, sliced
• 2 cups hearts of romaine salad mix