Chopped Veggie Salad with Watermelon and Feta Cheese

• 1 pound Campari or plum tomatoes, diced, drained
• 1 1/2 cups diced seeded watermelon
• 1 large green bell pepper, seeded, cut into 1/3-inch cubes
• 1/2 large English hothouse cucumber, seeded, cut into 1/3-inch cubes
• 1/2 cup very thinly sliced radishes
• 3 tablespoons olive oil, divided
• 10 ounces feta cheese, broken into small cubes (about 2 1/2 cups), divided
• 2 green onions, chopped, divided
• 1/4 cup thinly sliced fresh mint leaves, divided
• 1/2 cup plain Greek-style yogurt*
• 1 teaspoon dried oregano

Toss first 5 ingredients and 2 tablespoons oil in large bowl. Add half each of cheese, green onions, and mint. Mix remaining cheese, green onions, mint, and oil in processor; add yogurt and oregano. Process just to blend (do not over-mix or dressing will get thin). Season dressing with salt and pepper; mix into salad.

*A thick yogurt; sold at some supermarkets and at specialty foods stores and Greek markets. If unavailable, place regular yogurt in cheesecloth-lined strainer set over large bowl. Cover and chill overnight to drain