Lightly toast cumin seeds in a dry, medium skillet over low heat just until aroma is released, about 5 minutes. Transfer seeds to a blender. Add jalapeños, garlic, salt, pepper and lime juice, and puree until cumin seeds are finely ground. Add cilantro and olive oil and puree until smooth.
Slice steak across the grain into diagonal strips, about 4- x 1/2-inch in size. (Tough, yet flavorful steaks like this should always be cut across the grain.) Arrange meat in a shallow pan and generously cover meat all over with marinade with your hands. Cover and refrigerate for 1 to 2 hours.
About 30 minutes before cooking, remove meat from refrigerator and thread on skewers. Heat grill or broiler until it is very hot. Grill skewers until they are at their desired doneness, about 3 to 4 minutes per side. Serve hot with Aji Amarillo Aioli and Minted Chimichurri for dipping.
For aji amarillo aioli:
Combine ingredients in small bowl. Taste and adjust seasoning as necessary. Refrigerate until ready to use.
In a medium bowl, whisk together chimichurri ingredients. Let sit at least 30 minutes before serving, allowing flavors to combine.