This paper presents a three-dimensional theoretical study of extraordinary optical transmission through subwavelength hole arrays in optically thick metal films. The study shows good agreement with experimental data and develops an analytical minimal model that explains the transmission enhancement as due to tunneling through surface plasmons formed at metal-dielectric interfaces. The model identifies two regimes of tunneling: resonant through a "surface plasmon molecule" or sequential through two isolated surface plasmons, depending on the system's geometrical parameters. The study demonstrates that the extraordinary transmission effect, where light transmission through subwavelength holes is much higher than predicted by standard aperture theory, is due to surface plasmon tunneling. The transmission peaks are explained by resonant phenomena, with the maximum transmittance occurring when the distance between the surface plasmon reflection coefficient and an exponential factor is minimal. The physical origin of the effect is attributed to the formation of a "surface plasmon molecule" when surface plasmons on both metal surfaces combine. The study also considers the role of absorption and shows that it reduces the transmittance maxima but does not affect the peak positions or widths. The model is applied to both symmetric and asymmetric dielectric environments, showing that the transmission is reduced in the asymmetric case. The results indicate that the enhanced transmission is due to resonant tunneling through surface plasmons, with different transmission regimes depending on the film thickness. For small thicknesses, the transmission is resonant through "plasmon molecule" levels, while for larger thicknesses, the photon tunnels sequentially between surface plasmons. The findings highlight the potential of surface plasmons for efficient light transmission and focusing, with applications in photonic devices.This paper presents a three-dimensional theoretical study of extraordinary optical transmission through subwavelength hole arrays in optically thick metal films. The study shows good agreement with experimental data and develops an analytical minimal model that explains the transmission enhancement as due to tunneling through surface plasmons formed at metal-dielectric interfaces. The model identifies two regimes of tunneling: resonant through a "surface plasmon molecule" or sequential through two isolated surface plasmons, depending on the system's geometrical parameters. The study demonstrates that the extraordinary transmission effect, where light transmission through subwavelength holes is much higher than predicted by standard aperture theory, is due to surface plasmon tunneling. The transmission peaks are explained by resonant phenomena, with the maximum transmittance occurring when the distance between the surface plasmon reflection coefficient and an exponential factor is minimal. The physical origin of the effect is attributed to the formation of a "surface plasmon molecule" when surface plasmons on both metal surfaces combine. The study also considers the role of absorption and shows that it reduces the transmittance maxima but does not affect the peak positions or widths. The model is applied to both symmetric and asymmetric dielectric environments, showing that the transmission is reduced in the asymmetric case. The results indicate that the enhanced transmission is due to resonant tunneling through surface plasmons, with different transmission regimes depending on the film thickness. For small thicknesses, the transmission is resonant through "plasmon molecule" levels, while for larger thicknesses, the photon tunnels sequentially between surface plasmons. The findings highlight the potential of surface plasmons for efficient light transmission and focusing, with applications in photonic devices.