<p>The global shift toward sustainable diets has positioned legumes as essential protein sources. However, industrial processing generates significant volumes of by-products, such as husks and okara. This review provides a comprehensive framework on the valorization of these residues through emerging and biological technologies. We analyze the impact of ultrasound, high hydrostatic pressure (HPP), microwaves, extrusion, and fermentation on the techno-functional and sensory properties of legume by-products, emphasizing their role in replacing critical ingredients like fats, eggs, and hydrocolloids. Beyond functional improvements, the study highlights how these technologies influence sensory attributes, including texture refinement, color stability, and overall consumer acceptance in products such as snacks, bakery goods, and dairy analogues. Despite their potential, industrial implementation faces hurdles: technological limitations like the saturation effect in sonication, and food safety concerns regarding heavy metal migration and allergens. Economically, high capital investment and the microbiological instability of high-moisture by-products limit large-scale viability. This review concludes that overcoming these barriers requires a holistic approach that balances technological efficiency with sensory quality and safety. Consolidating legume by-products within a circular economy depends on addressing these gaps to ensure that the resulting innovative foods are not only sustainable and functional but also meet the texture and palatability expectations of the global market.</p>