Heat 1 tbsp oil in a skillet over high; pat meat dry, season with salt/pep + sear undisturbed 2 min; flip + cook, turning often, 1-2 min until browned (meat keeps cooking after being removed, be sure not to overcook for best results)

Meanwhile, tear corner of rice to vent + heat in microwave 90 sec (careful—it'll be hot!); if using a skillet, warm 2 min with 1 tbsp water

Wash + slice tomatoes in half; thinly slice ¼-½ the onion

Divide grains to bowls + bison; top with veggies + drizzle on 1-2 tbsp chimichurri