Preheat your oven to 400 degrees. Lightly toss the cherry tomatoes with olive oil & spread out on a baking sheet. Season generously with salt & pepper. Roast for 20-30 minutes, until the tomatoes are soft & the tops are browned (or blackened, depending on your flavors. I tend to like mine a little more cooked). Set aside.
In a small skillet, pour enough olive oil to cover the pan. Heat over medium heat. Add the onions to the pan & season with salt and pepper. Cook, over medium heat, for about 7-10 minutes or until they have caramelized. Mix in the minced jalapenos & chopped garlic. Cook for another 3-4 minutes. Mix in the chopped cilantro right before taking off the heat. Set aside.
Meanwhile - Heat enough olive oil to cover a large skillet over medium-high heat. Add the frozen cauliflower rice, breaking up any frozen clumps with a wooden spoon. Cook, stirring occasionally, for about 10-12 minutes, until the cauliflower rice has lightly browned. Pour in the chicken broth & bring to a boil. Lower the heat to medium & cook for about 7-10 minutes, or until the liquid has mostly cooked out. Season with salt, pepper, & garlic powder.
Stir the roasted tomatoes & sautéed onion mixture into the cauliflower rice. Stir in cooked chicken and/or black beans, if desired. Garnish with chopped cilantro, sliced avocado, & lime wedges.