Mix the soy sauce, pepper flakes, ginger, water, cornstarch and rice wine vinegar in a medium bowl. Add the sirloin, and stir to coat. Cover, and place in refrigerator to marinate during the next step.

In a large skillet or wok, stir 2 tablespoons of the olive oil, the sesame oil and the garlic over medium-high heat. Add the sliced peppers and scallions. Stir-fry until crisp-tender. Transfer to mixing bowl. In the same skillet or wok, add 1 tablespoon olive oil. Spoon beef with a slotted spoon into the skillet, reserving marinade for later use. Stir-fry beef until browned, then transfer to the bowl with the peppers. Add marinade to the skillet, and stir over medium-high heat until the sauce is thickened. Add the sirloin and pepper mixture to the skillet, stirring to coat with sauce and heat thoroughly. Spoon prepared rice into bowls, top with sirloin and pepper mixture, then serve.