Pat dry the shrimp with paper towels and add it to a large bowl. Drizzle with a lug of olive oil over the top and sprinkle with the sea salt, garlic powder, onion powder, cumin and paprika. Gently toss well to coat all over i the spice mix.
Thread 3 to 5 shrimps on each skewer and set aside on a plate for 15 minutes.
Meanwhile make the basil chimichurri. Add all the basil leaves to the bowl of a small food processor together with the garlic, olive oil and lime juice. Process until smooth. Transfer to a serving bowl and adjust seasonings to your taste until happy.
Heat up a large cast iron griddle ( on the stove top or on the grill), and place the shrimp skewers on top. Cook for about 45 seconds on each side, just enough for some grill marks to form and the shrimps to start curling up.
Transfer the grilled shrimp skewers to a serving platter and drizzle with the basil chimichurri. Garnish with some basil blossoms if available.