We recommend the conceptualization of computing as a critical literacy, and ground this conceptualization in considerations of historical and current realities in computing. The frameworks of connected learning and computational participation are recommended as guides for "doing" critical computing literacy. We present the findings from an interpretive case study of the "SciGirls" Code (SGC) program. This program was piloted with 16 after-school programs for middle school girls that engaged them in computer science (NSF #1543209). This research investigated girls' learning, attitudes, and participation involving 84 participants across 11 sites aged 10-14 and in 5th-8th grades. Through sharing a vignette from one site and highlighting findings from this study, we illustrate ways to "do" critical computing literacy and examine the potential of using connected learning and computational participation in designing more equitable computer science education offerings.