Purée ¾ cup thawed corn in a food processor or mini food processor; a few small pieces may remain. Transfer to a large bowl. Add diced red pepper, green onions, cilantro, oregano, salt, pepper, cayenne, flour and the remaining corn kernels. Mix well. Taste and adjust seasoning. Add egg and egg white; mix well.
If you like, preheat oven to 250°F to keep latkes warm. Line a plate with paper towels. Set out topping ingredients in small serving bowls.
Heat 3 tablespoons oil in a heavy nonstick skillet over medium heat until hot; a bit of batter added to pan oil should sizzle. For each latke, spoon 2 heaping tablespoons of corn mixture into pan. Flatten pancakes slightly with back of a spoon to 2½-inch rounds, pressing to compact them. Add more latkes to pan, leaving room to turn them over.
Fry latkes until golden brown on bottom, about 3 minutes. Turn very carefully with 2 pancake turners. Fry second side for about 2 minutes. Transfer to paper-towel-lined plate. Make more latkes from remaining batter.
When necessary, add a little more oil to pan and heat it before frying a new batch. Stir mixture before frying each new batch. Reduce heat if latkes brown too fast.
Serve hot, warm or room temperature, with toppings.