Heat a large pan over medium-high heat and add a splash of water (or oil if you prefer), the yellow onion and garlic. Sautee until soft and transparent. Add the rice and toast, stirring frequently, for a couple of minutes until you seen golden brown spots. Add the spices, tomatoes and sauce, stock, salt and pepper. Reduce the heat to low and cover the pan. Cook for about 20 minutes or until the rice is tender. Be careful not to overcook the rice, it may appear that not all the liquid has absorbed if the tomato sauce is sitting on top. Give it a stir and remove the pan from the heat.
While the rice cooks, grill the veggies. Heat a grill pan (or a regular pan if you don’t have one) over high heat. You can toss the veggies in a bit of oil if you like. Arrange the veggies in the grill pan; you may need to work in batches if they don’t all fit. Grill for a few minutes on each side until they are tender and a bit charred with grill marks.
Make a simple guacamole by mashing the avocado with the juice of half the lime and a pinch of salt. Slice the other half of the lime to serve in the bowls. When the veggies are done grilling, toss the tortillas onto the grill for a couple of seconds each side.
Divide the rice between your bowls and top with the grilled veggies, a dollop of guacamole, a slice of lime and a sprinkling of green onion or cilantro. Tuck a grilled tortilla into each bowl and serve.