For the vegan queso fresco: Drain the cashews and put them into a food processor. Add the lemon juice, oil, cumin and salt and pulse until you have a crumbled cheese consistency, adding 2 to 4 tablespoons of water as necessary.
For the rub: Mix the oil, lime juice, chili powder, paprika, cumin and salt in a casserole dish.
Peel back the corn husks to about an inch from the base of the corn ears, leaving the husks attached.
Bring 4 cups of lightly salted water to a boil in a large pot over high heat. Drop the corn into the boiling water, leaving the stalks hanging out of the top. Cook the corn until tender, 5 to 7 minutes; the ears should be a bright yellow color. Once done, remove from the heat and drain. Set the corn aside to cool.
Fire up your grill or grill pan to high heat. While that's warming up, roll each ear of corn in the rub and set on the grill. Grill the corn, turning every 30 seconds or so, until brown and slightly charred in places, 3 to 5 minutes total. Remove from the grill, roll in the remaining rub and top with vegan queso fresco before serving.