Recent advancements in eye tracking technology are driving the adoption of gaze-assisted interaction as a rich and accessible human-computer interaction paradigm. Gaze-assisted interaction serves as a contextual, non-invasive, and explicit control method for users without disabilities; for users with motor or speech impairments, text entry by gaze serves as the primary means of communication. Despite significant advantages, gaze-assisted interaction is still not widely accepted because of its inherent limitations: 1) Midas touch, 2) low accuracy for mouse-like interactions, 3) need for repeated calibration, 4) visual fatigue with prolonged usage, 5) lower gaze typing speed, and so on. This dissertation research proposes a gaze-assisted, multimodal, interaction paradigm, and related frameworks and their applications that effectively enable gaze-assisted interactions while addressing many of the current limitations. In this regard, we present four systems that leverage gaze-assisted interaction: 1) a gaze- and foot-operated system for precise point-and-click interactions, 2) a dwell-free, foot-operated gaze typing system. 3) a gaze gesture-based authentication system, and 4) a gaze gesture-based interaction toolkit. In addition, we also present the goals to be achieved, technical approach, and overall contributions of this dissertation research.