Prepare the vegetables by cutting the cauliflower and broccoli into equal-sized florets.
Mince the garlic and ginger, and set them aside.
Heat the vegetable oil in a large skillet or wok over medium-high heat.
Add the garlic and ginger to the skillet, stirring continuously for about 30 seconds.
Add the cauliflower and broccoli florets to the skillet, tossing to coat them in the flavored oil.
Stir-fry the vegetables for 4-5 minutes, until they are just tender but still crisp.
Pour the soy sauce, sesame oil, and rice vinegar over the vegetables, stirring to combine.
Season with salt and pepper to taste before serving.