Thoroughly rinse lentils. Cook them in plenty of water without salt, until they are soft but still have a bite to them. Drain when finished and rinse in cold water to stop cooking. Meanwhile, finely chop onion, scallions, jalapeno, parsley and coriander. Put everything in a bowl.
Crumble feta cheese and also add it to the bowl. Add lemon juice or vinegar, season with salt, black pepper and olive oil.
Heat some olive oil in a skillet. Toss cherry tomatoes in the hot oil for a few minutes and add them to the salad. Aldo add chopped roasted bell peppers, toasted nuts and seeds, if using.
Mix everything well and serve warm or chilled.