Cook rice and drain/warm black beans according to package directions; chop cilantro and juice limes.
Heat olive oil in a skillet over medium-high heat, season tilapia with salt and pepper, then cook 3 minutes per side until opaque and flaky.
Stir lime juice and cilantro into the warm rice and beans, then divide among plates.
Top each plate with one tilapia fillet, slice avocado, and garnish with extra cilantro.