Tip the peppercorns into a pestle and mortar and grind them as finely as you can. No pestle and mortar? Use a small, sturdy bowl and a jam jar or the end of a rolling pin to crush them.
Squeeze the juice from the Seville orange and the lime into the peppercorns. Add 1 tsp each ground cumin and dried oregano to the bowl. Peel and crush 1 garlic clove and stir that into the citrus mix with a pinch of salt.
Pat the pork escalopes dry with kitchen paper, then pop them in a dish and pour over the Seville orange mix. Turn to coat the escalopes in the marinade. Set aside for 10 mins to marinate.
While the pork marinates, tip the quinoa into a sieve and rinse under cold water for 1-2 mins to wash off the soapy coating. Tip the quinoa into a small pan. Peel the remaining garlic clove and add it to the pan. Pour in 150ml boiling water and add a small pinch of salt. Clamp a lid on the pan, bring to the boil and then turn the heat right down and gently simmer for 12 mins till the quinoa has absorbed all the water and is tender.
While the quinoa cooks, peel the onion and slice it into 8 wedges. Chop the tomatoes into 8 wedges each. Pop the veg in a bowl and add 2 tsp oil and a pinch of salt and pepper. Toss to mix.
Heat your grill to high. Line the grill pan with foil, or use a baking tray if your grill doesn't have a pan. Place a wire rack over the pan.
Place the pork escalopes on the wire rack (keep the marinade in the dish) and arrange the onion and tomatoes around them. Slide under the grill and cook for 6-8 mins, brushing with extra marinade from the dish every so often, till the pork escalopes are browned.
Take the pork out from under the grill and scoop the onion and tomato into the bowl you had them in earlier. Set aside. Turn the pork, brush with more marinade and grill for 5-6 mins till the pork escalopes are well browned.
Add the lamb's lettuce to the grilled veg and toss to mix. Squash the garlic clove into the quinoa and stir to mix the quinoa and garlic together. Serve the grilled pork escalopes with the garlicky quinoa and the salad.