If you have a mortar and pestle, use it to smash the olives and garlic together. Put the olive oil in a small saucepan, add the olive mixture, and stir over low heat, until the garlic is aromatic, a minute or so.
Remove from heat, and then add the walnuts, miso, tahini, oregano, and lemon juice. Use immediately, or cover and store refrigerated for a few days.