Step 1Drain and rinse the olives. Roll them dry between clean towels, then pound lightly with a mallet, meat pounder or heavy saucepan. Pick out and discard the pits. You should get about three-fourths cup.
Step 2Slice the garlic, then pound it in a mortar. By hand or in a processor, chop and combine the olives, garlic, capers and anchovy until you have a crumbly paste. Transfer it to a bowl.
Step 3Grate and work in about one-half teaspoon orange zest. Add the pastis or ouzo and the olive oil to taste.
Step 4Squeeze a few drops of orange juice into the tapenade just before serving. (Keeps well for a week or so refrigerated.)