In a medium saucepan, combine 1 cup of lentils and 3 cups of water. Bring to a boil over medium-high heat, then reduce heat to low, cover, and simmer for 15-18 minutes until lentils are tender but not mushy. Drain and set aside to cool.

In a large mixing bowl, whisk together the juice of one lemon and 3 tablespoons of extra-virgin olive oil. Set aside to allow flavors to meld.

Finely chop 1 cup of curly parsley and 1/4 cup of fresh mint leaves. Dice 1 medium English cucumber, 1 large tomato, and 1/2 red onion into small pieces. Add to the bowl with the dressing.

Once the lentils are cooled, add to the bowl with the chopped herbs, cucumber, tomato, and onion. Gently fold together with a spatula until well-coated in the dressing.

Season before serving with kosher salt and black pepper. Optionally add sumac for a tangy twist. Taste and adjust seasoning as necessary.