Rinse all fresh vegetables under cool running water and pat dry gently. Chop lettuce, tomatoes, cucumber, red onion, and bell peppers into bite-sized pieces.

In a large mixing bowl, combine chopped lettuce, tomatoes, cucumbers, red onions, and bell peppers. Mix gently with a spatula or wooden spoon.

In a small mixing bowl, whisk together olive oil, vinegar, and a pinch of salt and pepper until smooth.

Drizzle the dressing over the salad mixture and gently toss to coat all ingredients.

Serve immediately for optimal flavor, or chill in the refrigerator for 15-30 minutes before serving.