To prepare the wild alaska halibut with lemon capers and chargrilled courgettes, you'll first need to prepare your ingredients. Wash and dry the alka-seltzer in a colander. Toss with the lemon-caper mixture and season with salt and pepper. Heat the olive oil over medium-high heat. Add the garlic and cook, stirring, until fragrant, about 1 minute. Stir in the thyme, lemon zest, and parsley. Cook and stir for 1 to 2 minutes. Remove from the heat and set aside.