Combine first 3 ingredients in a bowl. Combine vinegar, 2 tablespoons olive oil, salt, pepper, and sugar; pour over pepper mixture. Toss. Cover and chill until ready to serve.
Arrange baguette slices on a large ungreased baking sheet. Brush or drizzle slices with 1/4 cup oil. Sprinkle with salt and pepper. Bake at 400° for 4 minutes or until barely toasted.
Spoon about 1 tablespoon pepper mixture onto each toast; top each with crumbled feta. Broil 5 1/2 " from heat 3 minutes or until bubbly and barely browned. Serve warm.