Place a medium pot over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Add the garlic to the pan and cook until aromatic, about 1 minute. Add the rice to the pan and toss to coat. Add the chicken stock to the pot, season lightly with salt and pepper and bring up to a bubble. Reduce the heat to low, cover the pot and steam until all of the liquid has been absorbed, about 15 minutes.
When the rice is ready, fluff with a fork and stir in the pimientos and red onion. Serve warm or at room temperature alongside Argentinean Surf-and-Turf Skewers with Chimichurri.