The privacy by design principle separates Monero from the rest of cryptocurrencies and yet maintains it regularly in the top 15 in market capitalization. The crucial privacy goal comes at the price of reduced expressiveness and scalability issues. First, Monero does not support any type of scripting language and current expressiveness is limited to exchange of coins between single addresses. Second, the privacy goal is achieved by building upon privacy tools with a high footprint in the ledger such as ring signatures and range proofs. This leads to a rapid ledger growth which in turn results in scalability issues. In this work, we lay the foundations to extend Monero expressiveness and mitigate the scalability issues. In particular, in this work, we present a novel linkable ring signature scheme DLSAG that enables for the first-time refund transactions natively in Monero. We formally prove that DLSAG achieves the security and privacy properties of interest, namely, unforgeability, signer ambiguity, and linkability. Interestingly, DLSAG enables several applications of interest in Monero such as atomic swaps. We further show how to leverage DLSAG to build different scalability solutions such as payment channels and payment-channel networks. DLSAG is currently being discussed within the Monero community to be adopted as a key building block to improve the expressiveness of Monero and mitigate the scalability issues. Pedro is a postdoctoral researcher at TU Wien. Before that, he got his PhD from Purdue University and he has been an intern researcher at leading blockchain companies such as IBM. His research interests include, among others, security and privacy of blockchain technologies. Recently, his research work has focused on payment-channel networks.