Prepare the dressing by whisking lemon juice, minced garlic, salt, black pepper, and chili flakes together. Slowly drizzle in olive oil while whisking until thickened.

Cook the lentils by rinsing and boiling with a bay leaf and enough water until tender, about 20-25 minutes. Drain and remove bay leaf.

Combine warm lentils with dressing in a mixing bowl, toss gently, and let cool for 5-10 minutes.

Add cucumber, bell peppers, green onions, parsley, and mint to the bowl and mix gently to combine.

Serve immediately or chill for a refreshing option. Store in an airtight container for up to 4 days.