This study investigates the impact of the size of salt particles on the perception of saltiness, dissolution behavior, and physicochemical properties with the goal of helping to optimize sodium reduction in solid foods while maintaining the taste/flavour. Static sensory evaluation demonstrated that fine-particle salt (<300 μm) elicited significantly higher saltiness intensity than coarse counterparts (≥400 μm), with the 100–200 μm range yielding the most pronounced perception. Time-Intensity analysis revealed that fine particles triggered an immediate perception of saltiness and a rapid peak, whereas coarse particles showed a delayed onset. Physicochemical characterization linked these sensory profiles to particle structure: dissolution rates increased exponentially as particle size decreased. Scanning electron microscopy (SEM) showed that fine particles possessed irregular shapes and high surface areas, while coarse particles formed porous cubic aggregates. Furthermore, X-ray diffraction (XRD) indicated higher crystallinity in smaller particles, contrasting with the reduced crystal integrity of larger, porous aggregates. Multivariate and multiblock analyses identified particle size as the primary driver of saltiness perception, with dissolution kinetics governing temporal onset and solubility determining maximum intensity. These findings suggest that finer particles (<300 μm) optimize saltiness delivery by maximizing initial sensory impact, providing a robust mechanistic strategy for developing high-quality, low-sodium solid foods.