Scallop Ceviche with Candied Citrus

Name: Scallop Ceviche with Candied Citrus
Ingredients: 1 pound bay scallops, sliced into 1/4-inch-thick rounds, or sea scallops, quartered and thinly sliced; 3 medium oranges; 8 to 10 limes; 2 ribs celery, peeled and diced; 1/2 cup diced red onion; 1 yellow tomato, seeded and diced; 2 Roma tomatoes, seeded and diced; 1/2 cup chopped scallions; 2 tablespoons extra-virgin olive oil; Freshly ground pepper; 1 cup sugar; 1/4 cup chopped fresh cilantro; Sea salt; Endive leaves or toasted bread slices, for serving (optional)