In a large saucepan, bring 1 quart of water to a boil. Season water and stir in lentils. Reduce heat to a simmer and cook lentils for 20-30 minutes or until just tender. The lentils should not be mushy. Drain off any remaining liquid.
Begin chopping the garlic clove and sprinkle with some salt. Using the flat side of the knife mash the garlic into a paste. In a medium bowl, whisk together the lemon juice and garlic paste. Whisk the olive oil into the lemon juice in a thin stream. Stir in the parsley, tomatoes, green pepper and basil. Gently mix in the drained lentils and toss to coat. Season to taste with salt and pepper