Put the lentils in a small pot with 1 1/2 cups of water, the smashed garlic clove, and half the onion. Season with salt, bring to a boil, and then simmer, covered, for 30 minutes, until your lentils are soft.
Use a slotted spoon to transfer the lentils to a food processor, leaving their cooking liquid in the pot (or, drain the lentils and reserve the cooking liquid).
Add a pinch of salt and pulse the lentils until they're as chunky or smooth as you'd like.
Heat the olive oil in a heavy skillet over medium heat. Add the onion and sauté until soft, 5 to 7 minutes. Then add the minced garlic clove, cumin, oregano, and red pepper flakes and cook for another minute, until the garlic is golden.
Add the lentils from the food processor and cook, stirring, until warmed through. If they're very dry, add some of the remaining cooking liquid to moisten. Taste and adjust salt and pepper. Squeeze the lime over top. Remove from heat.
Garnish with pickled onions, cilantro, and goat or feta cheese.