Cook the rice a day in advance and refrigerate to firm it up.
In a large bowl, combine the diced cucumber, bell peppers, tomatoes, and red onion.
Add the cooled, cooked rice to the bowl.
Drizzle olive oil and lemon juice over the mixture.
Season with salt and pepper to taste.
Toss the ingredients gently to mix evenly.
Layer the salad in a serving dish, starting with rice at the bottom.
Add a layer of the vegetable mixture on top of the rice.
Repeat the layers until all ingredients are used.
Top with crispy rice and mixed herbs for garnish.