Add the olive oil to a medium-hot skillet and stir in the garlic, continuing to stir as the garlic flavors the oil. Take care not to burn the garlic. Add in the red onion and sauté for 3 minutes; then add the kale. Sauté for 1 more minute, or until the kale has wilted. Add the cherry tomatoes, zucchini, and steamed broccolini. Sprinkle sea salt and grind fresh pepper over the whole dish and serve in the skillet for a rustic and wholesome side dish.