1. Cut the shrimp into 2 or 3 pieces, depending on their size. Put them in a bowl with the juice of half a lemon, olive oil, and chopped cilantro. Let marinate for 10 minutes in the refrigerator.
2. Rinse the quinoa and cook it for 10 minutes in boiling water. Drain and rinse.
3. Remove the skin and pit of the avocado, cut it into pieces, and drizzle all the pieces with the juice of the other half of the lemon.
4. Trim the base of the lamb's lettuce leaves if they still have their roots. Rinse the leaves. Shred the white cabbage.
5. Divide the ingredients into 2 jars, in the following order: quinoa, white cabbage, corn, avocado, shrimp, lamb's lettuce. Close the jar and refrigerate for a maximum of 24 hours.
6. Prepare the sauce: in a bowl, mix the vinegar, mustard, and cumin. Whisk for 1 minute with a fork. Add the oil and whisk again. Transfer the sauce to a separate bowl and season just before serving.