For the chimichurri: In a large non-reactive bowl, stir together the olive oil, mint, vinegar, chile flakes, honey, garlic, cilantro, parsley and lime juice. Season with salt and pepper; the sauce should be bright and slightly salty. I use a generous amount of cracked black pepper. Voila! You just made a great sauce for grilled steak.
For the steak: Marinate the steaks in 1 1/2 cups of the chimichurri sauce for at least 2 hours and up to 10 hours.
For the potatoes: Preheat the oven to 350 degrees F. Fill a baking tray with a 1/2-inch even layer of salt. In a large bowl, toss the potatoes with the oil and a few turns of cracked black pepper. Place the potatoes on the salt bed in an even layer. Roast in the oven until fork tender, about 1 hour. Cool slightly and brush off any excess salt.
For the aioli: In a food processor, combine the eggs and garlic. With the processor running, slowly add the oil in a steady stream, thinning down the aioli with the lemon juice to keep the emulsion from breaking. Add the zest, and pulse to fully incorporate. Season with some salt and pepper.
For the romesco: Preheat the oven to 350 degrees F. Wrap the garlic in a foil packet with the oil. Place on baking tray a roast in the oven for 30 minutes. Remove the tray from the oven, and add the almonds. Return the tray to the oven until the almonds are golden brown, 7 minutes.
In a blender, combine the garlic, almonds, vinegar and red peppers, and puree until smooth. Use immediately. Reserve any remaining sauce for another use; it can be kept in an airtight container for up to 1 week in the refrigerator.
Remove the steak from the marinade and sprinkle both sides with salt and pepper. Heat a large skillet over medium-high heat. Add the oil and sear the steaks, turning once, until desired temperature, about 1 1/2 minutes per side for medium-rare to medium, depending on your range and pan. Transfer to a cutting board to rest.
Reduce the heat to medium. Smash the fingerling potatoes into flat disks and sear in the pan until warm and crispy, about 2 minutes per side. Add more oil as necessary to prevent the potatoes from sticking to the pan.
To serve, spread 1 tablespoon of aioli in the center of each plate. Place 4 smashed fingerlings in the center of each plate on top of the aioli. Slice the steaks on a bias against the grain, arranging in a fan over the potatoes. Season with salt and pepper if desired. (I would.) Top the sliced steaks with a generous spoonful of the romesco. Garnish with the remaining 1/2 cup chimichurri and serve immediately.