We present an interdisciplinary methodology for designing interactive multi-modal technology for young children with autism spectrum disorders (ASDs). In line with many other researchers in the field, we believe that the key to developing technology in this context is to embrace perspectives from diverse disciplines to arrive at a methodology that delivers satisfactory outcomes for all stakeholders. The ECHOES project provided us with the opportunity to develop a technology-enhanced learning (TEL) environment that facilitates acquisition and exploration of social skills by typically developing (TD) children and children with autism spectrum disorders (ASDs). ECHOES' methodology and the learning environment rely crucially on multi-disciplinary expertise including developmental psychology, visual arts, human--computer interaction, artificial intelligence, education, and several other cognate disciplines. In this article, we reflect on the methods needed to develop a TEL environment for young users with ASDs by identifying key features, benefits, and challenges of this approach.