Heat oil in a large nonstick skillet over high heat. Sprinkle sirloin tips with 1/4 teaspoon salt and pepper. Add beef to pan, and cook 3 to 5 minutes, stirring frequently, or until desired degree of doneness. Remove beef from pan; set aside, and keep warm.
Reduce heat to medium-high. Add onion and peppers to pan; sauté 3 minutes. Add 2 tablespoons water; cook 1 minute.
Add beef to onion mixture; sprinkle with seasoning blend and remaining 1/4 teaspoon salt. Add 1/4 cup water to pan; bring to boil, scraping browned bits from bottom of pan. Cook, stirring constantly, 1 minute.