Gently toss 1 pound halved cherry tomatoes, 4 diced Persian cucumbers, ½ diced medium red bell pepper, ½ diced medium yellow bell pepper, 4 small diced medium radishes, ¼ small diced small red onion, ½ cup coarsely chopped fresh parsley leaves, and ¼ cup coarsely chopped fresh mint leaves together in a large bowl.
Drizzle 2 tablespoons plus 1 ½ teaspoons lemon juice and 2 tablespoons plus 1 ½ teaspoons extra-virgin olive oil over the salad.
Season with ¾ teaspoon kosher salt, ½ teaspoon ground sumac if using, and ⅛ teaspoon black pepper.
Toss to combine.
Taste and season with more kosher salt, black pepper, or lemon juice as needed.
Let sit for 10 minutes before serving.
