To prepare romesco, cut bell pepper in half lengthwise; discard seeds and membranes. Place bell pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 6 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 20 minutes. Peel and chop bell pepper. Place the chopped bell pepper in a food processor. Add tomato and next 10 ingredients (tomato through bread); process mixture until smooth.
Preheat oven to 350°.
To prepare tortilla, combine potato slices and 2 teaspoons olive oil on a jelly roll pan coated with cooking spray. Arrange potato slices in a single layer; sprinkle with 1/4 teaspoon salt and 1/4 teaspoon black pepper. Bake potatoes at 350° for 40 minutes or until tender, turning after 20 minutes. Remove potato slices from oven.
Combine egg substitute and eggs in a large bowl; stir with a whisk until foamy (about 2 minutes). Stir in potato slices, 1/4 teaspoon salt, and 1/4 teaspoon black pepper.
Heat a large nonstick skillet coated with cooking spray over medium-high heat. Pour egg mixture into pan, spreading potatoes in an even layer with a spatula. Reduce heat to medium; cook 4 minutes or until edges are set and bottom is lightly browned. Wrap handle of skillet with foil; broil 4 minutes or until set. Remove from oven; invert onto a serving platter. Cool at least 5 minutes or to room temperature before serving with romesco sauce.