In a deep pan over medium/high heat, add olive oil, rice, onion and garlic and stir to combine. Cook until onion is translucent (about 3 minutes), stirring periodically. Add curry powder and salt; mix well.
To the mixture, add water, lemon juice and lentils. Reduce heat to medium/low, cover pan and simmer gently about 30 minutes (if it starts to rapidly boil, reduce heat a little more). When lentils are tender and rice is cooked (test by tasting each), stir in spinach then cover for about 2 minutes to warm up/soften the spinach.
Remove from heat. Season to taste with salt and pepper, if desired. Top with tomatoes and serve.
**Before adding dry lentils to the pan, be sure that there are no little stones in the batch.