Place water, stock, or broth; lentils; and garlic in a medium saucepan. Bring to boiling. Reduce heat, cover, and simmer until lentils are tender (3 to 5 minutes for red lentils and 15 to 20 minutes for brown lentils). Do not overcook. Drain and place in a medium bowl. Set aside.
Stir together green onions, lemon juice, mint, olive oil, salt, pepper, allspice, and cinnamon. Pour over lentil mixture and stir to coat. Cover and refrigerate for at least 1 hour or up to to 8 hours.
To serve, let lentil mixture stand at room temperature for 25 to 30 minutes. Arrange spinach on a platter or in a serving bowl. Spoon lentil mixture over spinach. Sprinkle with apricots and pistachios. Makes 6 main-dish servings.