Cut the lamb in 1½-inch cubes. You should have about 20 cubes. Combine the garlic, rosemary, thyme, ¼ cup olive oil, red wine, vinegar, and 1 teaspoon salt in a medium bowl. Add the lamb cubes, cover with plastic wrap, and refrigerate overnight or for up to 2 days. Toss occasionally.
Heat a grill with coals. Spread them out in one dense layer and brush the grill with oil.
Cut the red onions in quarters and separate each quarter into 3 or 4 sections. Loosely thread 3 or 4 pieces of lamb onto skewers alternately with sections of onion. Sprinkle both sides of the lamb with salt and pepper. Next place the cherry tomatoes on skewers, threading them through the stems of the tomatoes. Brush the tomatoes with olive oil and sprinkle with salt and pepper. Place the lamb skewers on the hot grill and cook for 10 to 15 minutes, turning 2 or 3 times, until the lamb is medium-rare. Approximately 5 minutes before the lamb is done, place the tomato skewers on the grill, turning once, until seared on the outside but still firm inside.
For the sauce, bring the chicken stock, olive oil, and lemon juice to a boil in a small pot. Lower the heat and simmer for 5 minutes, or until reduced by half. Add the rosemary, salt, and pepper.
Melt the butter in a large saucepan. Add the shallots and cook them over medium-low heat for 3 minutes, until translucent. Add the chicken stock, salt, and pepper and bring to a boil. Turn off the heat. Stir in the couscous, cover the pan, and set aside for 10 minutes. Add the pine nuts, currants, and parsley and fluff with a fork to combine. Serve hot.
Serve the skewers on a mound of couscous with the sauce on the side.