Prep the herbs by washing them well and removing the stems. Shake off the excess water and set on kitchen towels to dry fully.
In a medium bowl, whisk together the lemon juice, olive oil, za'atar, salt and pepper to make the dressing, tasting and adjusting with more olive oil, lemon juice or salt as needed. Set aside.
Slice the radishes and cucumbers thinly and place in a large bowl. Finely chop the chives and add them to the bowl, then add the mint, parsley, cilantro and dill, reserving a small bit of each herb to use as garnish. Add the walnuts and feta.
Pour either half or all of the dressing over the salad, depending on how heavily dressed you like your salads, and toss to combine. Transfer to a serving dish and top with reserved herbs. Serve immediately.
