Step 1Combine oil and zest in small jar with lid.
Step 2Cut stems off parsley. Stack leaves in pile and chop into small pieces. Add to olive oil. Add garlic and 1/2 teaspoon salt to oil mixture, put on lid and shake vigorously. Taste and, if it seems flat, add 1/2 teaspoon more salt. Shake and taste again. Makes about 3/4 cup.
Step 1Place potatoes and whole eggs in large pot of salted water. Bring to boil and cook until potatoes are tender when pierced with a knife, 12 to 15 minutes. Be sure to poke to the center of the potato. Drain and place in large bowl.
Step 2When cool enough to handle, cut potatoes into quarters (don't peel). Place in bowl. Shell and quarter eggs and add them to bowl. Add tomato wedges.
Step 3Using your hands, lightly toss eggs and vegetables together. Salt lightly and toss to mix. Taste and add more salt if it tastes flat. Add half Gremolata to eggs and vegetables, toss and taste. If it seems shy of Gremolata, add a little more. Any leftover Gremolata should be put into small bowl and passed at the table. (Gremolata will keep a week refrigerated.)