Place the lentils in a pot with the water and bring to a boil. Cover and simmer for 30-35 minutes, until the lentils are tender but still retain their shape. Drain any excess water from the lentils and set them aside.
Heat the olive oil in a large skillet over a medium-high heat. Add the shallots and cook until they are softened, about 3 minutes. Add the spinach and cook until just wilted, about 2 minutes. Add the tomatoes, lentils, basil, parsley, and mint to the pan and stir to combine. Cook until warmed through, about 1 minute. Stir in the lemon juice, salt and pepper and serve.