Bring a saucepan of salted water to a boil. Add the lima beans and garlic and simmer until tender, 18 to 20 minutes. Drain and rinse under cold water to cool slightly (the beans should be warm but not hot).
Pulse the lima beans, garlic, parsley, lemon zest, lemon juice and 1 1/2 teaspoons salt in a food processor until just combined. With the motor running, pour in the olive oil and process until incorporated but still slightly chunky. Transfer to a bowl and top with the bacon. Serve warm or at room temperature with pita chips and/or vegetable sticks.
Buy lima beans frozen: They're bright green and buttery tasting. The olive-colored, mushy lima beans you remember from childhood were probably canned.