Thinly slice meat and put it into a glass/stone/ceramic mixing bowl
Put garlic, ginger, cornflour, soy sauce and rice wine vinegar into a mixing bowl and stir with meat to combine
Heat vegetable oil in a large frying pan or wok on medium-high heat and sauté onions for about 2 minutes or until soft
Add meat and fry until just cooked through, stirring occasionally
Add water to meat and heat until boiling. It will mix with the cornflour in the meat to make a sauce
Without putting the heat out, put the meat into a fresh mixing bowl
Add the vegetables into the frying pan and heat until just cooked through and still crisp, stirring occasionally
Add meat back into the frying pan and mix with vegetables until sauce is bubbling
Sprinkle with sesame oil to serve