In a large bowl, whisk together fresh lemon juice, minced garlic, salt, and black pepper. Gradually pour in extra-virgin olive oil while whisking until well-emulsified.

Rinse lentils under cold water and place them in a pot with a bay leaf and enough water to cover them by one inch. Bring to a boil, then cover and simmer for 20-25 minutes until tender; drain and discard bay leaf.

While the lentils are warm, transfer them to the bowl with the dressing and mix gently.

Chop cucumber, bell peppers, and green onions, and add to the lentils along with parsley and mint. Fold in gently.

Taste and adjust seasoning if necessary. Chill in the fridge for 30 minutes before serving, or serve at room temperature.