Combine water, wine, lemon, shallots, bay leaf, herbs, peppercorns and salt in the slow cooker and cook on high for 30 minutes.
Season the top of the salmon with salt and pepper and place in the slow cooker, skin side down. Cover and cook on low until salmon is opaque in colour and flakes gently with a fork. Start checking for desired doneness after 45 minutes to an hour and continue cooking until preferred doneness is reached (salmon can be held on the warm setting for several hours.)
Drizzle salmon with good-quality olive oil and sprinkle with coarse salt. Serve with lemon wedges on the side.