Cut loaf in half lengthwise; scoop out some bread from both halves to make a shallow boat the length of each half. Rub cut surfaces of bread with garlic.
Whisk together oil, vinegar, salt and pepper in small bowl.
Place arugula leaves over bottom half of bread. Top with roasted pepper, onion and cucumber. Arrange sprouts over top. Drizzle with vinegar mixture.
Replace top half of bread and press down gently.
Wrap in foil or plastic wrap. Refrigerate until ready to serve. Then unwrap and carefully cut crosswise into 8 equal pieces. Makes 8 servings.