Slice radish on thinnest setting on mandolin. Shave the purslane as thin as possible. Chiffonade cilantro and parsley. Mix lemon, lime, and olive oil with garlic, salt, and pepper and put dressing in a squeeze bottle. Toss the radishes, purslane, herbs, and lettuce with the dressing.
For the taquitos:
To make the taquitos: Clean and peel the potatoes and celery root. Cut potatoes in quarters and celery root in same-size pieces and cover in 2 cups water, milk, the bay leaf, 1 avocado leaf, salt, and pepper. Boil until soft, strain vegetables and reserve liquid.
Add the onions to a pan over medium heat. Add 1 tablespoon of oil and 1 avocado leaf. Cook onions until caramelized, stirring constantly to avoid burning.
Add potato, celery root, and caramelized onions in food processor and pulse until pureed smooth. Use cooking liquid if moisture is needed. Make sure to not add too much as loose filling will ooze out when frying. Add grated Manchego cheese, taste, and add salt and pepper if necessary.
Place filling in piping bag, and add 4 ounces of filling per tortilla. Once filled, roll and secure with toothpick. Heat vegetable oil and fry each taquito until golden brown, then drain on paper. To serve, add the dressed salad to each plate Divide up the taquitos and lay on top of salad. Garnish with queso fresco and a drizzle of crema Mexicana agria.