Prep the vegetables: dice tomatoes, onion, cucumber, and pepper very small.
Hydrate the couscous: Put the tomatoes and cucumber over uncooked couscous. Cover tightly with plastic wrap and let steam for 5 minutes.
Fluff the couscous: Uncover couscous and loosen with a fork. Season with salt and pepper. If needed add fresh lemon juice to help the couscous loosen and fully hydrate.
Mix: Add onion, bell pepper, lime juice, and olive oil. Mix well.
Chill: Refrigerate at least 1 hour.
Add herbs at the end: Right before serving, stir in chopped coriander, parsley, and mint. Taste and adjust seasoning.