In a skillet warm the olive oil. Add in sliced round steak and saute until browned. Place the browned beef and any juices in crock-pot. Mix together the Ponzu Sauce, ketchup, Pepsi cola, garlic and red pepper flakes. Pour over all. Cover and cook for 3 hours on low or until meat is tender and cooked through.
Add onion and bell peppers to crock pot. Stir to combine. Mix the cornstarch with a small amount of water. Turn crock-pot to high, stir in cornstarch mixture and continue to cook for 30 minutes.
After 30 minutes check seasoning and if necessary add salt and pepper to taste. Stir in tomato wedges and cook an additional 30 minutes.
Stir before serving. Serve on top of cooked rice of choice.