How to Make It
Using a vegetable peeler or mandoline, shave carrots, beet, and radishes lengthwise into 1/8-inch-thick slices. Submerge slices in a large bowl of ice water for 10 minutes. Drain well; pat dry.
Combine shaved vegetables and spring mix in a bowl; toss with 2 tablespoons oil and 2 tablespoons lemon juice. Sprinkle with sumac (if desired), 1/4 teaspoon salt, and pepper.
Whisk together tahini, zest, garlic, remaining 1 tablespoon oil, remaining 1 tablespoon juice, and remaining 1/4 teaspoon salt. Add 5 tablespoons warm water, 1 tablespoon at a time, whisking until smooth. Spread dressing across bottom of a large, shallow bowl. Pile salad on dressing; top with dates.