Combine minced shallot, 1 teaspoon lemon zest, 2 tablespoons lemon juice, ¼ teaspoon salt and ¼ teaspoon pepper in a large bowl; let stand for 10 minutes.
Whisk in 3 tablespoons mint, 3 tablespoons oil, 1 teaspoon mustard and 1 teaspoon honey.
Add chopped cucumber, sliced snap peas, chopped radishes and ½ cup feta; toss to coat.
