Step 1Peel the celery root with a large chef's knife. Cut it in half, then cut each half in thin slices. Stack the slices and cut them into thin rectangular sticks. It's easiest to do this in 3 or 4 batches. Place in a mixing bowl.
Step 2Combine the olive oil, lemon juice and garlic in a blender and puree at high speed until emulsified, about 30 seconds. Add the carrot tops and the salt and puree just until they are finely chopped and still visible in specks in the pale green dressing, 30 seconds. Taste and add more salt if necessary.
Step 3Pour the dressing over the celery root and stir gently to combine. The salad should be very lightly dressed, with flecks of green clinging to the celery root sticks.
Step 4Transfer to a serving bowl. This salad can be made up to an hour in advance and held at room temperature. The celery root will soften slightly and become silkier.