How to Make It
Pour the lemon juice into a large bowl. Working with 1 artichoke at a time, pull off the tough outer leaves. Using a small knife, slice 1/4 inch off the top of each artichoke, then trim and peel the stems. Very thinly slice each artichoke lengthwise and add to the bowl. Toss with the lemon juice and ½ teaspoon of salt. Let stand for 30 minutes, tossing occasionally.
Spread the arugula and radicchio on a platter. Using a slotted spoon, lift the artichokes from the lemon juice and scatter over the greens. Sprinkle with the herbs.
Whisk the olive oil with the remaining lemon juice in the large bowl and season with salt and pepper. Drizzle the dressing over the salad; serve.