Warm 1 Tbsp. oil in a saucepan over medium-high heat. Add rice and cook, stirring, until fragrant, 1 to 2 minutes. Add 1 1/2 cups water and 1/2 tsp. salt. Bring to a boil, cover, reduce heat to low and simmer until water is absorbed, about 15 minutes.
Warm remaining 1 Tbsp. oil in a skillet over medium heat. Add garlic and sauté until fragrant, about 30 seconds. Stir in 1/2 cup water, beans, chili powder and cumin. Bring to a simmer and cook until most of liquid has evaporated, 5 to 7 minutes, stirring once or twice. Season lightly with salt.
Combine avocados and lime juice in a medium bowl. Divide rice among 4 bowls. Top with bean mixture, corn, tomatoes and avocados. Serve with garnishes and chips on the side, if desired.