Heat a skillet over medium heat for a minute or so until it gets warm.
Add the onions, garlic, ginger, parsley, tarragon, sea salt and black pepper and cook for 3 minutes, stirring frequently so the ingredients don't stick to the bottom of the pan. If they start to stick, add just a little splash of water.
Add mushrooms and 2 tablespoons of water and cook for 4 minutes, stirring intermittently.
Place the walnuts, lemon juice and the onion/mushroom mixture in a food processor and process until smooth, for about 5 minutes.
Stop processing occasionally and use a rubber spatula to push down any pate that has collected on the side of the food processor.
Let chill for at least an hour before serving. Serve with cucumber rounds or on toasted sprouted bread.