Lightly coat an 8-inch nonstick skillet with flared sides or a crepe pan with cooking spray. Heat skillet over medium-high heat.
In a medium bowl beat together eggs, salt, and cayenne pepper with a rotary beater or wire whisk until frothy. Pour into the prepared skillet; cook over medium heat. As egg mixture sets, run a spatula around edge of skillet, lifting egg mixture so that the uncooked portion flows underneath.
Continue cooking and lifting edges until egg mixture is set but is still glossy and moist. Sprinkle with cheese and chives. Top with 3/4 cup of the spinach and 2 tablespoons of the Red Pepper Relish. Using the spatula, lift and fold an edge of the omelet partially over filling. Top with the remaining 1/4 cup spinach and 1 tablespoon of the relish. (Reserve the remaining relish for another use.) Cut the omelet in half. Makes 2 servings.
Red Pepper Relish
In a small bowl combine red pepper, onion, vinegar, and pepper. Makes about 2/3 cup.