Prepare the Vegetables: Clean all the vegetables thoroughly. Trim the ends from the asparagus and French green beans, and cut the asparagus into 1-inch pieces. Trim the Brussels sprouts and cut them in half. Slice the small red onion into thin wedges and mince the garlic.
Cook Onion and Garlic: Place a large, non-stick skillet over medium heat. Add a small amount of water (about 2 tablespoons) to the skillet to prevent sticking. Add the sliced red onion to the skillet with a pinch of salt. Sauté until the onion starts to soften, about 3-5 minutes. Add the minced garlic to the skillet and cook for another minute until fragrant, being careful not to let it burn.
Add the rest of the vegetables: To the skillet, with the onion and garlic, add the asparagus, Brussels sprouts, and French green beans. Continue to sauté, stirring frequently, for about 5 minutes or until the vegetables are slightly tender but still crisp. Add a little more water if needed to prevent sticking.
Add liquid and cook: Pour in the vegetable stock, add the juice of 1 lemon, and a pinch of salt, stirring well to combine and to loosen any bits stuck in the pan. Cook for an additional 4-5 minutes, or until most of the liquid has evaporated and the vegetables are coated but not dry.
Season: Remove from the heat—grate lemon zest over the cooked vegetables and season with salt and pepper to taste.
Toast the almond slices (optional): If using, toast the almond slices in a dry pan over medium heat until golden and fragrant.
Serve: Transfer the salad to a serving dish, and sprinkle the almond slices and the dried cranberries, if using, over the top of the salad. It can be served warm or at room temperature, according to your preference.