Technological tools are means by which online teaching could encourage the engagement of students, especially elementary students. The present research studies how elementary teachers develop their use of technological tools in their asynchronous and synchronous online teaching, specifically when this online teaching occurs during emergency education. The research was conducted in the academic year 2019/2020. We interviewed two elementary teachers, where one of them taught asynchronous lessons more than synchronous, while the second taught synchronous lessons more than asynchronous. We analyzed the data using two frameworks: one for interaction type and one for engagement type. The research results indicated that different interaction types influenced teachers' decisions to use technological tools. In addition, what concerned the teachers' use of tools at the beginning was the cognitive engagement, but they advanced towards focusing on behavioral and the affective engagement.